GC3-Q020A Page 1
APPLICATION MANUAL
8 string WLED DRIVER IC
AP2001A
CONTENTS
1 . DESCRIPTION 2
2 . FEATURES 2
3 . APPLICATIONS 2
4 . PIN CONFIGURATION 2
5. Ordering Information 2
5 . PACKAGE OUTLINE 3
6 . BLOCK DIAGRAM 4
7 . ABSOLUTE MAXIMUM RATINGS 5
8 . ELECTRICAL CHARACTERISTICS 6
9 . TEST CIRCUIT 8
10 . TYPICAL CHARACTERISTICS 9
11 . PIN DESCRIPTION 19
12 . CIRCUIT DESCRIPTION 23
13 . APPLICATION INFORMATION 27
14 . NOTES 34
15 . OFFICES 34
AP2001A
GC3-Q020A Page 2
8 string WLED DRIVER IC
AP2001A
1. DESCRIPTION
AP2001A is a white LED driver IC for scanners and
copiers. AP2001A contains a current mode PWM boost
converter and 8 LED current sources. AP2001A can drive
up to 8-channels of 12 white LEDs in series. The LED
current accuracy is within ±3.5%. The adjustable LED
current, up to 33mA, is set by an external resistor.
AP2001A includes a fixed frequency oscillator of
1.5MHz.
Dimming is controlled directly from an external PWM
signal with a frequency range of 100Hz to 20kHz.
AP2001A protection circuits include LED open/short
protections, CH short protection, VOUT short protection,
Boost-FET over-current protection, over-temperature
protection, and over-voltage protection
AP2001A has a wide input voltage range from 8V to 28V.
AP2001A is available in a 24-pin HQFN package.
2. FEATURES
Drive up to 96 (12s x 8ch) LEDs
LED Current Accuracy ±3.5% (max.)
LED Current Matching ±1.5% (typ.)
LED Max current: 33mA/ch
Dimming by External PWM signal (20kHz Max)
Switching Frequency: 1.5MHz (fixed)
Wide Input Voltage Range: 8V~28V
Internal Power MOS-FET, 0.6W
LED open/short protection
CH short protection
Over-voltage / Boost-FET Over-current protection
Thermal shutdown
Flag output for LED open/short
24-pin HQFN with thermal pad
3. APPLICATIONS
Scanner LED light source for Multifunction Printer
Lighting installation driver
4. PIN CONFIGURATION
HQFN4040B-24
CH7
CH6
CH5
CH4
CH3
CTM
OVP
FAULT
COMP
VIN
CH2 LX
5. Ordering Information
H: Lead free and Halogen free
A P 2 0 0 1 A 4 1 - E 2
Version
Package code
Q7: HQFN4040 B-24
Environment code
Grade
1: Consumer Product
Storage direction
E2: 1pin Left Upper side
A
Q 7 H
Temperature range
4: Ta=-40 ~ 85°C
AP2001A
GC3-Q020A Page 3
5. PACKAGE OUTLINE
HQFN4040B-24
AP2001A
GC3-Q020A Page 4
6. BLOCK DIAGRAM
UVLO
OSC
SWITCH LOGIC
TIMER
LATCH
LDO
5.0V
11
CH3
12
CH2
13
CH1
OVP
VIN
VDC
FAULT
CTM ISETGND
5
22
20
24
1
LOW SIDE
CURRENT
SINK
4
CURRENT
SENSE
CH6
CH7
CH8
OVER VOLTAGE
PROTECTION
ERROR
AMP
DIMMING
CONTROL
DRIVER
TSD
THERMAL
SHUTDOWN
221
PWM
COMPARATOR
PWM
23
COMP
OPE
TSD
CURRENT
SENSE
CURRENT
SENSE
DRIVER,
TIMER
VDC
DRIVER,
DIMMING
VOLTAGE
SELECT
LED TIMER
8
CH
SHORT
3
FLG
LX
PGND
19
18
DRIVER
+
-
REG 3.0V
VOUT SHORT
PROTECTION
LED SHORT
PROTECTION
8
VOUT
SHORT
CH OPEN
PROTECTION
8
CH4
CH5
CH3
CH1
CH2
10
CH4
7
CH7
8
CH6
9
CH5
6
CH8
1.2V
1.2V
0.1V
0.5V
0.5V
OPE
OPE
TSD
FLAG
CONTROL
14
CLR
LED
OPEN/SHORT
FLAG
VDC
1.5uA
15
EN0
16
EN1
ALL LED
OPEN/ SHORT
17
EN2
FAULT
CONTROL
AP2001A
GC3-Q020A Page 5
7. ABSOLUTE MAXIMUM RATINGS
Ta=25°C
Parameter Symbol Value Units Conditions
VIN, FAULT VIN,VFAULT
-0.3 to +35 V *1
LX VLX -0.3 to +47 V *1
CH1-8 VCH -0.3 to +45
VDC, FLG, CLR, PWM
EN0, EN1, EN2 - -0.3 to +6 V *1
ISET, CTM, OVP, COMP - -0.3 to (VDC+0.3) V *1
CH1-8 Drive Current ICH 40 mA
Continuous Power
Dissipation PD 2000 mW *2, *3
Operating Temperature Range
TOP -40 ~ +85 °C
Storage Temperature Range TSTG -55 ~ +150 °C
Note:
*1. All voltages are with respect to the potential at the GND pins (GND, PGND).
*2. PD must be decreased at the rate of 20.0mW/°C for operation above 25°C.
*3. AP2001A mounted on an FR-4 type evaluation board (4 layer 50 mm ´ 40 mm, t= 1.0mm)
AP2001A
GC3-Q020A Page 6
8. ELECTRICAL CHARACTERISTICS
Suggested Operating Voltage Range
Parameter Symbol Value Units
Conditions
VIN Operating Voltage Range
VIN 8 ～ 28 V
VIN=24V, PGND=GND=0V, PWM=5V, EN0=5V, EN1=EN2=0V, RISET=45.5kΩ, TA=+25°C, unless otherwise noted.
Value
Parameter Symbol MIN TYP MAX Units
Conditions
DC-DC CONVERTER
Input Voltage Range VIN 8 28 V
Operating Current
(Boost FET ON) IDD 6 12 mA
Shutdown Current ISD 90 180 μA
Standby Current ISTB 250 500 μA PWM =0V
UVLO Threshold
(Failing Edge) VUVLO 4.5 6.0 7.5 V UVLO ON, VIN
UVLO Hysteresis VHYS_UVLO
0.3 V UVLO ON→OFF, VIN
Source Current for CTM ICTMP 500 μA VCTM=3V, PWM=5V
Sink Current for CTM ICTMN 1.5 μA VCTM=1V, PWM=0V
CTM Pin Threshold Voltage VOPE 0.45 0.5 0.55 V IC ON, VCTM
CTM Pin Hysteresis VHYS_OPE 0.1 V IC ON→OFF, VCTM
Internal Oscillator Operating
Frequency of Switching FOSC_LX 1.1 1.5 1.9 MHz
Internal Switch RDS-ON RLX 600 mΩ
ILX=+30mA
Internal Switch
OFF Leak Current ILEAK_LX 0.1 1.0 μA VLX=45V
Maximum Duty Cycle DMAX_LX 88 93 %
COMP Output High Voltage VOH_COMP 4.45 4.85 V ICOMP=-10μA
COMP Output Low Voltage VOL_COMP 0.15 0.3 V ICOMP=+10μA
Minimum CH Voltage VCH_MIN 1.08 1.2 1.32 V
Current Sink Circuit and Brightness Control
Maximum LED Current ILED_MAX 33 mA
RISET= 18 kΩ (MIN case)
ILED1 19.3 20 20.7 mA
RISET=45.5 kΩ
CH1~CH8
LED Drive Current
ILED2 28.95 30 31.05 mA
RISET=30.33 kΩ
CH1~CH8
ΔILED1 ±1.5 %
RISET= 45.5 kΩ,
100
(%)
_
_)81( ´
-
=
D
-
AVELED
AVELEDMAXorMINCH
LED
I
II
I
LED Current Difference
Between Channels
ΔILED2 ±1.5 %
RISET= 30.33 kΩ,
100
(%)
_
_)81( ´
-
=
D
-
AVELED
AVELEDMAXorMINCH
LED
I
II
I
AP2001A
GC3-Q020A Page 7
Electrical Characteristics (Continued)
Value
Parameter Symbol MIN TYP MAX Units
Conditions
LDO
Output Voltage VDC 4.75 5.0 5.25 V
PROTECTION
Over-Voltage Protection
Threshold (OVP) VOVP 1.17 1.2 1.23 V
Maximum Current Limit of
Internal Switch ILX_LIMIT 1.5 A
FAULT Output
ON-Resistance RFAULT 100 Ω IFAULT=+10mA
INTERFACE
PWM Frequency Range
of Brightness Control FPWM 0.1 20 kHz
Input High Voltage VIH 2.1 V PWM, CLR, EN0,EN1,EN2
Input Low Voltage VIL 0.7 V PWM, CLR, EN0,EN1,EN2
FLG Output ON-Resistance RFLG 100 Ω IFLG=+10mA
AP2001A
GC3-Q020A Page 8
9. TEST CIRCUIT
VOH_COMP
VOL_COMP
TM
VCH_MIN
ILED1
PGND
EN1FLG
CH8 CH1
CLR
EN2
EN0
GND
1
6
7 12
13
18
1924
PWM
VDC
ISET
VDC
1uF
ILED_MAX
ILED2
RFLG
TM FPWM
RISET VIH VIL
VIH VIL
VIH VIL
VIH VIL
VIH VIL
AP2001A
GC3-Q020A Page 9
10. TYPICAL CHARACTERISTICS
VIN=24V, PGND=GND=0V, PWM=5V, EN0=5V, EN1=EN2=0V, RISET=45.5kW, TA=+25°C, unless otherwise noted.
LED Current vs. ISET Pin Resistance LED Current Matching vs. LED Current
0
5
10
15
20
25
30
35
40
45
0 20 40 60 80 100
ISET Resistance(kΩ)
LED Current(mA).
0.0
0.5
1.0
1.5
2.0
2.5
0 10 20 30 40
LED Current(mA)
LED Current Matching(%).
LED Current vs. PWM Duty(RISET =45.5kΩ)
0
5
10
15
20
25
0 10 20 30 40 50 60 70 80 90 100
PWM Duty(%)
LED Current(mA).
LED Current vs. Input Voltage (RISET =45.5kΩ) LED Current vs. Temperature (RISET =45.5kΩ)
10
12
14
16
18
20
22
24
26
28
30
5 10 15 20 25 30
Input Voltage(V)
LED Current(mA).
RISET=45.5kΩ
10
12
14
16
18
20
22
24
26
28
30
-40 -20 0 20 40 60 80 100 120
Temperature(°C)
LED Current(mA).
RISET=45.5kΩ
AP2001A
GC3-Q020A Page 10
LED Current Matching vs. Temperature (RISET=45.5kΩ)
0.0
0.5
1.0
1.5
2.0
2.5
3.0
-40 -20 0 20 40 60 80 100 120
Temperature(°C)
LED Current Matching(%).
LED Current vs. Input Voltage (RISET=30.33kΩ) LED Current vs. Temperature (RISET=30.33kΩ)
20
22
24
26
28
30
32
34
36
38
40
5 10 15 20 25 30
Input Voltage(V)
LED Current(mA).
RISET=30.33kΩ
20
22
24
26
28
30
32
34
36
38
40
-40 -20 0 20 40 60 80 100 120
Temperature(°C)
LED Current(mA).
RISET=30.33kΩ
LED Current Matching vs. Temperature (RISET=30.33kΩ)
0
0.5
1
1.5
2
2.5
3
-40 -20 0 20 40 60 80 100 120
Temperature(°C)
LED Current Matching(%).
AP2001A
GC3-Q020A Page 11
Switching Frequency vs. Input Voltage Switching Frequency vs. Temperature
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
2.0
5 10 15 20 25 30
Input Voltage(V)
Switching Frequency(MHz) .
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
2.0
-40 -20 0 20 40 60 80 100 120
Temperature(°C)
Switching Frequency(MHz) .
Maximum Duty Cycle vs. Input Voltage Maximum Duty Cycle vs. Temperature
90
92
94
96
98
100
5 10 15 20 25 30
Input Voltage(V)
Maximum Duty(%) .
90
92
94
96
98
100
-40 -20 0 20 40 60 80 100 120
Temperature(°C)
Maximum Duty(%) .
Operating Supply Current vs. Input Voltage Operating Supply Current vs. Temperature
4.0
4.2
4.4
4.6
4.8
5.0
5.2
5.4
5.6
5.8
6.0
5 10 15 20 25 30
Input Voltage(V)
Operating Current(mA) .
4.0
4.2
4.4
4.6
4.8
5.0
5.2
5.4
5.6
5.8
6.0
-40 -20 0 20 40 60 80 100 120
Temperature(°C)
Operating Current(mA) .
AP2001A
GC3-Q020A Page 12
Standby Current vs. Input Voltage Standby Current vs. Temperature
0
50
100
150
200
250
300
350
400
5 10 15 20 25 30
Input Voltage(V)
Standby Current(uA).
0
50
100
150
200
250
300
350
400
-40 -20 0 20 40 60 80 100 120
Temperature(°C)
Standby Current(uA).
Shutdown Current vs. Input Voltage Shutdown Current vs. Temperature
0
20
40
60
80
100
120
140
160
180
200
5 10 15 20 25 30
Input Voltage(V)
Shutdown Current(uA) .
0
20
40
60
80
100
120
140
160
180
200
-40 -20 0 20 40 60 80 100 120
Temperature(°C)
Shutdown Current(uA) .
VDC Output Voltage vs. Input Voltage VDC Output Voltage vs. Temperature
4.0
4.2
4.4
4.6
4.8
5.0
5.2
5.4
5.6
5.8
6.0
5 10 15 20 25 30
Input Voltage(V)
VDC Output Voltage(V) .
4.0
4.2
4.4
4.6
4.8
5.0
5.2
5.4
5.6
5.8
6.0
-40 -20 0 20 40 60 80 100 120
Temperature(°C)
LDO Output Voltage(V) .
AP2001A
GC3-Q020A Page 13
Input High Threshold Voltage vs. Input Voltage Input High Threshold Voltage vs. Temperature
0.0
0.5
1.0
1.5
2.0
2.5
3.0
5 10 15 20 25 30
Input Voltage(V)
Input High Voltage(V) .
0.0
0.5
1.0
1.5
2.0
2.5
3.0
-40 -20 0 20 40 60 80 100 120
Temperature(°C)
Input High Voltage(V) .
Input Low Threshold Voltage vs. Input Voltage Input Low Threshold Voltage vs. Temperature
0.0
0.5
1.0
1.5
2.0
2.5
3.0
5 10 15 20 25 30
Input Voltage(V)
Input Low Voltage(V) .
0.0
0.5
1.0
1.5
2.0
2.5
3.0
-40 -20 0 20 40 60 80 100 120
Tepemerature(°C)
Input Low Voltage(V) .
Minimum CH Voltage vs. Input Voltage Minimum CH Voltage vs. Temperature
1.00
1.05
1.10
1.15
1.20
1.25
1.30
1.35
1.40
5 10 15 20 25 30
Input Voltage(V)
Minimum CH Voltage(V) .
1.00
1.05
1.10
1.15
1.20
1.25
1.30
1.35
1.40
-40 -20 0 20 40 60 80 100 120
Temperature(°C)
Minimum CH Voltage(V) .
AP2001A
GC3-Q020A Page 14
UVLO Threshold Voltage vs. Temperature UVLO Hysteresis Range vs. Temperature
5.0
5.2
5.4
5.6
5.8
6.0
6.2
6.4
6.6
6.8
7.0
-40 -20 0 20 40 60 80 100 120
Temperature(°C)
UVLO Threshold Voltage(V) .
UVLO ON
UVLO OFF
0
0.1
0.2
0.3
0.4
0.5
-40 -20 0 20 40 60 80 100 120
Temperature(°C)
UVLO Hysteresis Range(V).
OVP Reference Voltage vs. Input Voltage OVP Reference Voltage vs. Temperature
1.00
1.05
1.10
1.15
1.20
1.25
1.30
1.35
1.40
5 10 15 20 25 30
Input Voltage(V)
OVP Reference Voltage(V).
1.00
1.05
1.10
1.15
1.20
1.25
1.30
1.35
1.40
-40 -20 0 20 40 60 80 100 120
Temperature(°C)
OVP Reference Voltage(V).
Over Current Protection Threshold vs. Input Voltage Over Current Protection Threshold vs. Temperature
0.0
0.5
1.0
1.5
2.0
2.5
3.0
5 10 15 20 25 30
Input Voltage(V)
LX Current Limit(A).
0.0
0.5
1.0
1.5
2.0
2.5
3.0
-40 -20 0 20 40 60 80 100 120
Temperature(°C)
LX Current Limit(A).
AP2001A
GC3-Q020A Page 15
LED Short Threshold Voltage vs. Input Voltage LED Short Threshold Voltage vs. Temperature
10.0
10.5
11.0
11.5
12.0
12.5
13.0
13.5
14.0
5 10 15 20 25 30
Input Voltage(V)
LED Short Voltage(V).
10.0
10.5
11.0
11.5
12.0
12.5
13.0
13.5
14.0
-40 -20 0 20 40 60 80 100 120
Temperateure(°C)
LED Short Voltage(V).
Thermal Shutdown vs. Input Voltage
130
140
150
160
170
5 10 15 20 25 30
Input Voltage(V)
Temperature(°C)
FAULT RDS-ON vs. Input Voltage FAULT RDS-ON vs. Temperature
0
20
40
60
80
100
120
140
5 10 15 20 25 30
Input Voltage(V)
FAULT Rds-ON(W)
0
20
40
60
80
100
120
140
-40 -20 0 20 40 60 80 100 120
Temperature(°C)
FAULT Rds-ON(W)
AP2001A
GC3-Q020A Page 16
FLG RDS-ON vs. Input Voltage FLG RDS-ON vs. Temperature
0
20
40
60
80
100
5 10 15 20 25 30
Input Voltage(V)
FLG Rds-ON(
W)
0
20
40
60
80
100
-40 -20 0 20 40 60 80 100 120
Temperature(°C)
FLG Rds-ON(
W)
AP2001A
GC3-Q020A Page 17
VIN-EN-PWM Start up waveform
VIN=24V
1CH(Blue) Inductor Current 500mA/DIV
2CH(Light Blue) VOUT 10V/DIV
3CH(Purple) PWM 2V/DIV
4CH(Green) EN 5V/DIV
1ms/DIV
VIN-PWM-EN Start up wave form
VIN=24V
1CH(Blue) Inductor Current 500mA/DIV
2CH(Light Blue) VOUT 10V/DIV
3CH(Purple) PWM 2V/DIV
4CH(Green) EN 5V/DIV
1ms/DIV
At the start, CH1 LED open state
VIN=24V
1CH(Blue) PWM 5V/DIV
2CH(Light Blue) FLG 5V/DIV
3CH(Purple) VOUT 20V/DIV
4CH(Green) Inductor Current 500mA/DIV
2ms/DIV
AP2001A
GC3-Q020A Page 18
CH1-VOUT short state
VIN=24V
1CH(Blue) FLG 5V/DIV
2CH(Light Blue) CH1 20V/DIV
3CH(Purple) VOUT 20V/DIV
4CH(Green) CH1 Current 20mA/DIV
2ms/DIV
CH1-GND short state
VIN=24V
1CH(Blue) FAULT 5V/DIV
2CH(Light Blue) CH1 1V/DIV
3CH(Purple) VOUT 20V/DIV
4CH(Green) CH1 Current 50mA/DIV
2ms/DIV
At the start, all CH open
VIN=24V
1CH(Blue) PWM 5V/DIV
2CH(Light Blue) VIN 20V/DIV
3CH(Purple) VOUT 20V/DIV
4CH(Green) Inductor Current 500mA/DIV
1ms/DIV
AP2001A
GC3-Q020A Page 19
11. PIN DESCRIPTION
No. Name Equivalent Circuit Description
1 VDC
LDO output. The LDO supplies power to internal circuits with
regulated 5.0V. The LDO always operates when there is an
input at VIN. If this pin is shorted to GND, the IC limits the
load current to approximately 40mA (typ.). Connect a 1.0uF
ceramic capacitor between this pin and GND.
2 PWM
Active-high PWM control input and IC enable.
PWM pin has internal 200kΩ pull-down resistor.
3 FLG
Error flag output, N-channel open drain output. This pin is
“OFF” during the IC in normal operation. When one or more
of the LED channel is in open or short condition, this pin turns
“ON”.
IC condition can be observed by pull-up resistor to VDC pin.
Error flag can be reset by using CLR pin. If this function is not
used, connect this pin to GND.
4 ISET
LED current setting pin. Connect a resistor between this pin
and GND to program the LED current. If this pin shorts to
GND, the boost converter and the CH pin turn off.
5 GND Ground.
6 CH8
6
VDC
White LED current stabilizer pin. CH8 pin sinks constant
current from the LED string. Connect the cathode of the LED
string to this pin. When CH8 pin voltage falls to 0.2V or lower,
fault timer protection circuit starts the count. If not used, leave
it unconnected.
7 CH7
7
VDC
White LED current stabilizer pin. CH7 pin sinks constant
current from the LED string. Connect the cathode of the LED
string to this pin. When CH7 pin voltage falls to 0.2V or lower,
fault timer protection circuit starts the count. If not used, leave
it unconnected.
AP2001A
GC3-Q020A Page 20
No. Name Equivalent Circuit Description
8 CH6
8
VDC
White LED current stabilizer pin. CH6 pin sinks constant
current from the LED string. Connect the cathode of the LED
string to this pin. When CH6 pin voltage falls to 0.2V or lower,
fault timer protection circuit starts the count. If not used, leave
it unconnected.
9 CH5
9
VDC
White LED current stabilizer pin. CH5 pin sinks constant
current from the LED string. Connect the cathode of the LED
string to this pin. When CH5 pin voltage falls to 0.2V or lower,
fault timer protection circuit starts the count. If not used, leave
it unconnected.
10 CH4
10
VDC
White LED current stabilizer pin. CH4 pin sinks constant
current from the LED string. Connect the cathode of the LED
string to this pin. When CH4 pin voltage falls to 0.2V or lower,
fault timer protection circuit starts the count. If not used, leave
it unconnected.
11 CH3
11
VDC
White LED current stabilizer pin. CH3 pin sinks constant
current from the LED string. Connect the cathode of the LED
string to this pin. When CH3 pin voltage falls to 0.2V or lower,
fault timer protection circuit starts the count. If not used, leave
it unconnected.
12 CH2
12
VDC
White LED current stabilizer pin. CH2 pin sinks constant
current from the LED string. Connect the cathode of the LED
string to this pin. When CH2 pin voltage falls to 0.2V or lower,
fault timer protection circuit starts the count. If not used, leave
it unconnected.
13 CH1
13
VDC
White LED current stabilizer pin. CH1 pin sinks constant
current from the LED string. Connect the cathode of the LED
string to this pin. When CH1 pin voltage falls to 0.2V or lower,
fault timer protection circuit starts the count. If not used, leave
it unconnected.
AP2001A
GC3-Q020A Page 21
No. Name Equivalent Circuit Description
14 CLR
The error flag clear pin. When this pin is pulled to a high level,
the LED open or short flag will be cleared. During high level,
the IC stops operation.
CLR pin has an internal 200kΩ pull-down resistor.
15 EN0
IC enable and channel select pin. The channel preferred to be
used can be selected by the combination of EN0, EN1, and
EN2.
EN0 pin has an internal 200kΩ pull-down resistor.
16 EN1
IC enable and channel select pin. The channel preferred to be
used can be selected by the combination of EN0, EN1, and
EN2.
EN1 pin has an internal 200kΩ pull-down resistor.
17 EN2
IC enable and channel select pin. The channel preferred to be
used can be selected by the combination of EN0, EN1, and
EN2.
EN2 pin has an internal 200kΩ pull-down resistor.
18 PGND Power ground for internal switching FET.
19 LX
19
PGND
Internal power MOS-FET pin, N-channel open drain output.
20 FAULT
20
N-channel MOS-FET open drain output pin. Internal MOS-
FET is “ON” during the IC in normal operation. MOS-FET
turns “OFF” when:
-Fault timer protection stops the operation of the IC
-IC detects the OVP pin short condition
-All 8 channel pins are in open or short condition.
When the number of operating channels is selected to 7 or less
by the enable pin, this pin will not turn “OFF”.
By connecting a P-channel FET, this pin can be used as on/off
switch for VIN power line, and also as a protection to abnormal
operation. If not used, connect to GND.
AP2001A
GC3-Q020A Page 22
No. Name Equivalent Circuit Description
21 CTM 21
VDC
PWM signal buffer output. Connect a 0.1uF ceramic capacitor
between this pin and GND. When PWM signal is “HIGH”
level, CTM pin is pulled up to VDC and the capacitor will be
charged. When PWM signal is “LOW” level, IC will sink and
discharge the capacitor. In standby mode, IC will start
operation when CTM pin voltage is more than 0.5V. When
CTM pin voltage falls to less than 0.4V, IC will enter standby
mode.
22 OVP 22
VDC
Over-voltage protection pin. The resistor divided output
voltage is applied to this pin. IC will limit the output voltage
rise when the OVP pin voltage rises to 1.2V. When the OVP
pin voltage falls to less than 0.1V, such as an output short,
boost converter, CH1-8 pin and FAULT pin turns off.
23 COMP
Error amplifier output pin Connect a resistor and a capacitor
between this pin and ground for phase compensation.
24 VIN
24
VDC
IC power supply pin. This pin is the voltage input pin for the
internal LDO which supplies the power to the internal circuits.
Connect a 1.0uF ceramic capacitor between this pin and GND.
- THERMAL
PAD - Ground.
AP2001A
GC3-Q020A Page 23
12. CIRCUIT DESCRIPTION
12-1. PWM Boost Converter
AP2001A includes a current mode PWM boost converter.
It contains a boost FET, 8 LED current sink channels,
1.5MHz fixed frequency switching oscillator and some
protection circuits.
The PWM boost converter and the LED current sinks are
controlled by an input signal to the PWM pin. The fast
transient response of the current mode architecture easily
handles the LED load variation caused by the PWM
dimming signal or a sudden input voltage change. .
The boost converter continuously monitors the various
CH pins’ voltages and selects the CH pin (that is
connected) with the maximum forward voltage of the
LED strings to use as the feedback signal. The feedback
reference voltage is 1.2V. The inverting amplifier creates
a COMP pin signal equaling the difference between the
feedback signal and the reference voltage of the error
amplifier. The COMP pin signal minus the boost FET
current is compared with the slope compensation signal to
determine the boost FET on-time. When the load is
decreased, the boost FET on-time is decreased.
12-2. 5V Low-Dropout Regulator
AP2001A includes an internal low-dropout regulator
(LDO) for supplying internal circuits. When VIN is higher
than 8.0V, this LDO generates 5.0V supply to the VDC
pin.
For regulating LDO output, it should be connected to a
1.0uF bypass capacitor between the VDC pin and GND.
12-3. Enable
When EN0, EN1, and EN2 are low, the IC shuts down,
and consumption current is about 90mA (when VIN =24V).
When EN0, EN1, or EN2 is high, the IC is in standby
mode.
The IC is operational when the CTM voltage is over 0.5V
and the PWM pin input is high.
If the CTM voltage is under 0.4V, the IC is in standby
mode.
12-4. Switching Frequency
AP2001A includes a 1.5MHz fixed frequency switching
oscillator for the boost converter.
12-5. PWM Control
AP2001A uses an external PWM signal for direct
dimming. When the PWM dimming signal is high, the
LED current is the value set by the RISET resistor. When
the PWM dimming signal is low, the LED current is 0mA.
The pulse width of the PWM dimming signal should be
greater than 30ms.
12-6. LED Constant Current Sink
AP2001A includes 8 LED constant current sink channels.
It can drive up to 8 channels of 12 white LEDs in series.
The LED current can be set up to 33mA per channel for a
maximum total LED current of 264mA. The LED current
is set by the external resistor, RISET, which is connected
between the ISET pin and GND. The LED current of all
channels is the same value. The LED current of each
string is approximately as follows;
)(
910
)( W
=kR
mAI
ISET
LED
When RISET is 45.5kΩ, the LED current is approximately
20mA. The LED current accuracy is ±3.5% among all
channels. The CH pin voltages are always monitored after
standby mode. The CH pin with the lowest voltage will
be the CH that has the maximum LED forward voltage of
all channels. It is the CH pin used for the feedback
voltage. All other CH pins’ voltages are higher than the
feedback pin’s voltage.
12-7. Under Voltage Lockout (UVLO)
If VIN falls below 6.0V, the IC will stop operation except
for the LDO and UVLO circuits. When VIN comes back
above 6.3V, the IC will enter standby mode. The
hysteresis on UVLO is 0.3V.
12-8. Over-Voltage Protection (OVP)
To maintain a safe level at the output voltage, AP2001A
includes an over-voltage protection function that monitors
the output of the resistive voltage divider from the output
voltage. If the OVP pin voltage rises above 1.20V, the
boost converter will turn off, but the LED current sources
remain in the operating mode. When the OVP pin voltage
falls below 1.20V, the boost converter will restart. The
OVP function prevents an LED string open or a sharp
increase of VIN from damaging the IC.
12-9. Fault Timer
AP2001A includes a fault timer protection by timer latch
circuit. When CH pin short protection, over-temperature
protection, or over current protection is engaged, the
counter of the timer circuit starts.
The Boost converter and constant current drivers are
stopped after a count of 7680 cycles of the switching
frequency and the FAULT pin is turned off.
If the IC is latched off by the fault timer, it can be reset
by shutting down the IC via an EN0, EN1, and EN2 low
level input or UVLO ON for VIN below 4.5V.
AP2001A
GC3-Q020A Page 24
12-10. LED Constant Current Sink Fault
protection
AP2001A has fault protection functions that detect the
abnormal conditions of open/short LEDs and CH pin
shorts. These protections start with the operation of the
boost converter and continue to be monitored after soft-
start.
12-10-1. LED Open Protection
If LED strings are disconnected due to a damaged LED or
a CH pin connection failure, the LED current through
those strings will be 0mA. The boost converter will
continue to operate, raising the output voltage trying to
get the LED current through those strings to the proper
set value. If this happens, the IC and other components
will be destroyed by the boost FET’s over current and/or
output voltage.
AP2001A has two kinds of CH pin open detection
functions, which operate during startup and afterwards.
When a disconnected CH pin is detected, this pin
becomes a hi-impedance and the boost converter doesn’t
control this pin.
i) In the case of one or more CH pins being open at
startup:
If the IC is being used with one or more CH pins
disconnected, an initial diagnosis of the CH pins
detects this condition during standby mode.
If the output voltage is rising up to the OVP setting
voltage, the LED timer circuit starts counting. After a
count of 1920 cycles of the switching frequency, any
CH pins that the LED current sinks are not driving to
1/5 of the LED current setting value will be
disconnected, therefore, these LED current sources
will be turned off.
ii) If one or more CH pin’s becomes open during steady
state (after the initial diagnosis of CH pins at startup):
If the output voltage is rising up to the OVP setting
voltage, the LED timer circuit starts counting. After a
count of 1920 cycles of the switching frequency, any
CH pins that the LED current sinks are not driving to
the LED current setting value will be disconnected,
therefore, these LED current sinks will be turned off.
If all CH pins are disconnected the boost converter
and the LED current sources will turn off completely.
This function guarantees that the LED current sinks
are only used for connecting LED strings. If a high
level signal is input into the CLR pin or VIN falls
below 4.5V, this protection function will be reset.
12-10-2. LED Short Protection
If a short circuit occurs between an LED anode an
cathode due to LED damage and/or an external resistive
connection, etc. in one or more of the LED strings, the
forward voltage of the affected LED strings will be lower
than the none affected strings. The output voltage is the
same for all channels; therefore, the affected LED strings
will have a higher CH pin voltage. If any of the CH pin
voltages reach 12V above ground and the error amplifier
is in a stable status, the LED timer circuit starts counting.
After a count of 1920 cycles of the switching frequency,
any CH pins that exhibit this LED short condition will be
disconnected; therefore, these LED current sources will
be turned off. If a high level signal is input into the CLR
pin or VIN falls below 4.5V, this protection function will
be reset.
12-10-3. CH pin Short Protection
If the CH pin is connected to GND, the boost converter
will operate to increase the output voltage to try to reach
the LED current set value. Also, it will overdrive the
remaining LEDs damaging or destroying the LEDs the IC
and other components.
AP2001A has the CH pin short protection function. If the
CH pin voltage is below 0.2V and this condition
continues, the IC will detect the CH pin short condition to
GND. The boost converter and the LED current sources
will immediately turn off.
12-11. Over-Temperature Protection
AP2001A has the over-temperature protection function. If
the IC temperature exceeds +125°C, the boost converter
and LED current sources will turn off completely by fault
timer.
12-12. VDC Short Protection
If the VDC pin is connected to GND, the load current of
the internal LDO will be restricted to below 40mA
preventing the IC from overheating.
12-13. Over-Current Protection
AP2001A has the over-current protection function. If the
IC detects that the current of the boost FET is over 1.5A,
the boost FET will turn off. This monitor is reset on each
cycle of the boost frequency. If it continuously detects an
over current situation, the boost converter and the LED
current sinks will turn off completely based on the fault
timer circuit.
AP2001A
GC3-Q020A Page 25
12-14. VOUT Short Protection
AP2001A has VOUT short protection function. If the OVP
pin voltage falls below 0.1V, the IC will detect the OVP
pin short condition to GND and the boost converter and
the LED current sinks will immediately turn off. Then if
the OVP pin voltage rises over 0.1V, the boost converter
and the LED current sinks will immediately turn on.
This protection internal protection does not protect the
overall circuit because the over-current condition still
exists through the schottky diode. To protect against this,
an input voltage ON/OFF switch can be added by
connecting a P-channel FET to the FAULT pin. When the
disable signal of the FET for fault timer is latched, the
FAULT pin becomes ON-state and the P-channel FET
turns off, the current route to GND is cut off (Fig.1).
SWITCH LOGIC
TIMER
LATCH
OVP
FAULT
22
20
CURRENT
SENSE
CH6
CH7
CH8
OPE
TSD
CURRENT
SENSE
CH
SHORT
LX
PGND
19
18
DRIVER
VOUT
SHORT
CH4
CH5
CH3
CH1
CH2
TSD
Fig. 1. Protection for short circuit of VOUT and GND
Note: When the number of operating channels selected is
7 or less using the EN0, EN1, and EN2 pins, the FAULT
pin will not turn “OFF”, therefore this protection will not
work.
12-15. Choose the Number of LED CH
AP2001A has an ON/OFF control function of CH5, CH6,
CH7, and CH8 using the pins EN0, EN1, and EN2.
EN0
EN1
EN2
CH1
~CH4
CH5 CH6 CH7 CH8
L L L OFF OFF OFF OFF OFF
H L L ON ON ON ON ON
L H L ON ON ON ON OFF
L L H ON ON ON OFF OFF
H H L ON ON OFF OFF OFF
H L H ON ON OFF OFF OFF
L H H ON ON OFF OFF OFF
H H H ON OFF OFF OFF OFF
Fig. 2. LED string selected by combination of EN
CH pins that are turned off via EN0, EN1, and EN2 are
not monitored by the Error Flag function.
12-16. Error Flag
The operating condition of AP2001A can be checked by
using the FLG pin and the FAULT pin. The FLG pin and
the FAULT pin are N-channel open drain outputs. .
i) FLG pin；
When one or more of the LED strings are in open or
short condition, this pin turns "ON".
The operating condition of the IC can be observed by
connecting a pull-up resistor to VDC. The Error flag
can be reset by using the CLR pin.
As noted above, CH pins that are turned off via EN0,
EN1, and EN2 are not monitored by the Error Flag
function.
ii) FAULT pin；
The FAULT pin turns “OFF” when:
-The fault timer function stops the operation of the
IC
-The IC detects the OVP pin short condition
-All 8 channel pins are in open or short condition.
When the number of operating channels selected is 7
or less using the EN0, EN1, and EN2 pins, this pin
will not turn “OFF”.
This flag is cleared by the UVLO operation for input
voltages lower than 4.5V or shutdown mode for EN0,
EN1, and EN2 (input “LOW” level). In this case, the
fault flag is reset and turned on.
AP2001A
GC3-Q020A Page 26
12-17. POWER DISPATION
Maximum Power Dissipation
0
500
1000
1500
2000
2500
-50 0 50 100 150
Ta (℃)
Pd_max (mW).
Evaluation Board
FR-4 type
x=50mm, y=40mm, t=1.0mm
Thickness of copper foil:35mm
Thickness of inner coat copper foil:25mm
Note： Please consult Maximum Power Dissipation graph above and verify your thermal design. This IC assumes that
the actual maximum operating temperature is less than 125°C, because even with over-temperature protection
this IC has the possibility of operating over 125°C.
The actual maximum power dissipation of your design should be verified because this IC is not warranted if the
over-temperature protection function has been used.
AP2001A
GC3-Q020A Page 27
13. APPLICATION INFORMATION
13-1. Application Circuit
・ Input Voltage： VIN =22~26V
・ LED Number： 12 white LEDs in series /8 parallel /96pcs (VOUT MAX: 38V)
・ LED Current： 26mA
・ Inductor Peak Current ： 850mA max
・ Switching Frequency： 1500kHz
・ OVP Setting： 44.5V
UVLO
OSC
SWITCH LOGIC
TIMER
LATCH
LDO
5.0V
11
CH3
12
CH2
13
CH1
OVP
VIN
VDC
FAULT
CTM ISETGND
5
22
20
24
1
LOW SIDE
CURRENT
SINK
4
CURRENT
SENSE
CH6
CH7
CH8
OVER VOLTAGE
PROTECTION
ERROR
AMP
DIMMING
CONTROL
DRIVER
TSD
THERMAL
SHUTDOWN
221
PWM
COMPARATOR
PWM
23
COMP
OPE
TSD
CURRENT
SENSE
CURRENT
SENSE
DRIVER,
TIMER
VDC
DRIVER,
DIMMING
VOLTAGE
SELECT
LED TIMER
8
CH
SHORT
3
FLG
LX
PGND
19
18
DRIVER
+
-
REG 3.0V
VOUT SHORT
PROTECTION
LED SHORT
PROTECTION
8
VOUT
SHORT
CH OPEN
PROTECTION
8
CH4
CH5
CH3
CH1
CH2
10
CH4
7
CH7
8
CH6
9
CH5
6
CH8
1.2V
1.2V
0.1V
0.5V
0.5V
OPE
OPE
TSD
FLAG
CONTROL
14
CLR
LED
OPEN/SHORT
FLAG
VDC
1.5uA
15
EN0
16
EN1
ALL LED
OPEN/ SHORT
17
EN2
FAULT
CONTROL
CIN1
L
D
CCOMP2
CCOMP1
RCOMP ROVP3
ROVP1
VDC
RFLG
RISET1CCTM
CDC
CIN2
RISET2
ROVP2
COUT2
COUT1
AP2001A
GC3-Q020A Page 28
13-2. Component List
Circuit Symbol Silk
Part Number Value Company Remark
RFLG R15
100kΩ Flag pull-up
ROVP1 R9
- 510 kΩ,±0.5% - OVP setting
ROVP2 R10
- 360 kΩ,±0.5% - OVP setting
ROVP3 R11
24 kΩ,±0.5% OVP setting
RSET1 R5
- 33kΩ,±0.5% -
RSET2 R6
- 2.0kΩ,±0.5% -
LED current setting
26mA
Resistor
RCOMP R12
Short - - Phase compensation
CIN1 C1
GRM31CR71H475K 4.7uF/50V MURATA Input bypass capacitor
CIN2 C6
CM21X5R105K50AB 1.0uF/50V KYOCERA
IC bypass capacitor
CDC C10
CM105X5R105K16AB
1.0uF/6.3V KYOCERA
VDC bypass capacitor
CCTM C9
CM05B104K16AB 0.1uF/16V KYOCERA
CCOMP1 C7
CM05B104K16AB 0.1uF/16V KYOCERA
Phase compensation
CCOMP2 C8
CM05B104K16AB 0.1uF/16V KYOCERA
Phase compensation
COUT1 C3
GRM31CR71H475K 4.7uF/50V MURATA Output capacitor
Capacitor
COUT2 C4
GRM31CR71H475K 4.7uF/50V MURATA Output capacitor
Diode D D - More than
VR=60V, Io=1A
-
Inductor L L #A916CY-100M D63CB 10uH TOKO
AP2001A
GC3-Q020A Page 29
13-3. Application Specification
■LED Current vs. Input Voltage ■LED Current Matching vs. Input Voltage
Vin vs. ILED
20
22
24
26
28
30
22 23 24 25 26
Vin(V)
ILED(mA).
ILED1 ILED2
ILED3 ILED4
ILED5 ILED6
ILED7 ILED8
Vin vs. LED Current CH to CH Tolerance
-5
-4
-3
-2
-1
0
1
2
3
4
5
22 23 24 25 26
Vin(V)
LED Current
CH to CH Tolerance(%).
ILED1 ILED2
ILED3 ILED4
ILED5 ILED6
ILED7 ILED8
■Efficiency vs. Input Voltage
Vin vs. Efficiency
60
65
70
75
80
85
90
95
100
22 23 24 25 26
Vin(V)
Efficiency(%)
100
IV
_IV
Efficiency
ININ
TOTALLEDOUT ´
×
×
= [%]
■LED Current vs. PWM Signal Duty ■LED Current Matching vs. PWM Signal Duty
LED Current vs. PWM Signal Duty
0
5
10
15
20
25
30
10 20 30 40 50 60 70 80 90 100
PWM Signal Duty(% )
LED Current(mA).
ILED1 ILED2
ILED3 ILED4
ILED5 ILED6
ILED7 ILED8
LED Current CH to CH Tolerance vs. PWM Signal Duty
-5
-4
-3
-2
-1
0
1
2
3
4
5
10 20 30 40 50 60 70 80 90 100
PWM Signal Duty(% )
LED Current
CH to CH Tolerance(%).
ILED1 ILED2
ILED3 ILED4
ILED5 ILED6
ILED7 ILED8
AP2001A
GC3-Q020A Page 30
13-4. Operating wave form
VOUT=38.0V, ILED=26mA
(Light Blue) VOUT 100mV/Div (AC)
(Blue) Inductor Current 500mA/Div
VIN
22V
24V
26V
AP2001A
GC3-Q020A Page 31
13-4-1. Inductor Current waveform on start-up
VOUT=38.0V, ILED=26mA
(Purple) PWM 2V/Div (Green) EN 2V/Div
(Light Blue) VOUT 10V/Div (Light Blue) VOUT 10V/Div
(Blue) Inductor Current 500mA/Div (Blue) Inductor Current 500mA/Div
(Green) EN 5V/Div (Purple) PWM 5V/Div
VIN VIN→EN→PWM VIN→PWM→EN
22V
24V
26V
AP2001A
GC3-Q020A Page 32
13-4-2. LED Current waveform on state-up
VOUT=38.0V, ILED=26mA
(Purple) PWM 2V/Div (Green) EN 2V/Div
(Light Blue) VOUT 10V/Div (Light Blue) VOUT 10V/Div
(Blue) LED Current 10mA/Div (Blue) LED Current 10mA/Div
(Green) EN 5V/Div (Purple) PWM 5V/Div
Vin VIN→EN0→PWM VIN→PWM→EN0
22V
24V
26V
AP2001A
GC3-Q020A Page 33
13-4-3. LED Current waveform at PWM dimming
VIN =24V, VOUT=38.0V, ILED=26mA
PWM Signal Duty=20, 50, 90%, PWM Frequency =3, 10kHz, EN=5V
(Green) EN 2V/Div (Green) EN 2V/Div
(Light Blue)VOUT 10V/Div (Light Blue) VOUT 10V/Div
(Blue) LED Current 10mA/Div (Blue) LED Current 10mA/Div
(Purple) PWM 5V/Div (Purple) PWM 5V/Div
PWM
Duty
PWM Frequency=3kHz PWM Frequency=10kHz
20%
50%
90%
AP2001A
GC3-Q020A Page 34
14. NOTES
Please be sure that you carefully discuss your planned
purchase with our office if you intend to use the products in
this application manual under conditions where particularly
extreme standards of reliability are required, or if you intend
to use products for applications other than those listed in this
application manual.
Power drive products for automobile, ship or aircraft
transport systems; steering and navigation systems,
emergency signal communications systems, and any
system other than those mentioned above which include
electronic sensors, measuring, or display devices, and
which could cause major damage to life, limb or property
if misused or failure to function.
Medical devices for measuring blood pressure, pulse,
etc., treatment units such as coronary pacemakers and heat
treatment units, and devices such as artificial organs and
artificial limb systems which augment physiological
functions.
Electrical instruments, equipment or systems used in
disaster or crime prevention.
Semiconductors, by nature, may fail or malfunction in
spite of our devotion to improve product quality and
reliability. We urge you to take every possible precaution
against physical injuries, fire or other damages which may
cause failure of our semiconductor products by taking
appropriate measures, including a reasonable safety margin,
malfunction preventive practices and fire-proofing when
designing your products.
This application manual is effective from Sep. 2010. Note
that the contents are subject to change or discontinuation
without notice. When placing orders, please confirm
specifications and delivery condition in writing.
ASAHI KASEI TOKO POWER DEVICES is not
responsible for any problems nor for any infringement of
third party patents or any other intellectual property rights
that may arise from the use or method of use of the products
listed in this application manual. Moreover, this application
manual does not signify that ASAHI KASEI TOKO
POWER DEVICES agrees implicitly or explicitly to license
any patent rights or other intellectual property rights which it
holds.
None of the ozone depleting substances (ODS) under the
Montreal Protocol are used in our manufacturing process.
15. OFFICES
If you need more information on this product and other
ASAHI KASEI TOKO POWER DEVICES products, please
contact us.
ASAHI KASEI TOKO POWER DEVICES CORPORATION
13-45, Senzui 3-chome, Asaka-shi, Saitama-ken
351-0024, Japan
TEL: +81-48-460-1870 (Marketing Department)
FAX: +81-48-460-1600
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