Low-saturation, current-controlled
bidirectional motor driver
Overview
The LB1843V is a low-saturation bidirectional motor driver
with output current limitation and detection functions. This
design is ideal for controlling the loading motor in a video
camera.
Features
.Output current limiter and detector built in
.Low-saturation voltage bidirectional bridge circuit built in:
VOsat = 0.40 V typ. at 400 mA
.Practically no current drain (0.1 µA or less) in standby mode
.Input-linked reference voltage built in
.Thermal shutdown circuit built in
.Requires little space, since few external components are
needed and the IC is contained in a small SSOP-20 package
Package Dimensions
unit : mm
3179A-SSOP20
[LB1843V]
SANYO : SSOP20
Specifications
Absolute Maximum Ratings at Ta = 25°C
Parameter Symbol Conditions Ratings Unit
Maximum supply voltage VCC max 10.5 V
Maximum output current Im max 800 mA
Applied input voltage VIN –0.3 to +10 V
Allowable power dissipation Pd max With board ( 50 ×35 ×1.6 mm
3
) 800 mW
Operating temperature Topr –20 to +80 °C
Storage temperature Tstg –40 to +150 °C
Allowable Operating Ranges at Ta = 25°C
Parameter Symbol Conditions Ratings Unit
Supply voltage VCC 3.0 to 9.0 V
VMvoltage VM2.2 to VCC V
High-level input voltage VIH 3.0 to 9.0 V
Low-level input voltage VIL –0.3 to +0.7 V
LIR input voltage VLIR 0.5 to VCC–1.0 V
Output current limitation Ilimit 50 to 350 mA
Ordering number: EN 4385B
Monolithic Digital IC
LB1843V
SANYO Electric Co.,Ltd. Semiconductor Bussiness Headquarters
TOKYO OFFICE Tokyo Bldg., 1-10, 1 Chome, Ueno, Taito-ku, TOKYO, 110-8534 JAPAN
O3096HA(II) No.4385-1/6
Electrical Characteristics at Ta = 25°C, VCC = 7.2 V
Parameter Symbol Conditions min typ max Unit
Supply current ICC0 During standby 0.1 10 µA
ICC1 During bidirectional operation, no load 9 13 mA
ICC2 During braking 12 18 mA
Output saturation voltage Vsat1 IO= 200 mA (upper side + lower side) 0.20 0.30 V
Vsat2 IO= 400 mA (upper side + lower side) 0.40 0.60 V
Reference voltage Vref IVref = 1 mA 1.85 2.0 2.15 V
Set output current Ilimit Resistance between VCC and VM=1Ω,
when LIR = 2 V 165 185 205 mA
Input current IIN VIN = 5 V 90 150 µA
RD saturation voltage VRDsat IO= 1 mA 0.3 V
Output current limit is determined by the following equation (Rfis the sensing resistance between VCC and VM):
Ilimit =V
LIR/10Rf(A)
The input range for VLIR is 0.5 to VCC–1.0 (V)
Pd max – Ta
Specified board (50 ×35 ×1.6 mm
3
glass epoxy)
Allowable power dissipation, Pd max – mW
Ambient temperature, Ta – °C
LB1843V
No.4385-2/6
Block Diagram and Sample Application Ciruit
Pin Assignment
Thermal
shut down
Decoder Limit detection
VCC = 3 to 10.5 V R
f
= 0.47 to 2 Ω
0.001 µF
to 0.01 µF
Top view
Notes: .Connect both VMpins
(motor power supply/sensing pins).
.Connect both P-GND pins
(motor power supply GND pins).
.Connect S-GND (control power
supply GND pin) to the
microcontroller’s GND.
LB1843V
No.4385-3/6
Truth Table
Input Output Mode
IN1 IN2 OUT1 OUT2
L L off off Standby
HLHLForward
LHLHReverse
H H L L Brake
Output Current Limitation and Detector Output
DEL OUT output RD
HLimit L
Non-limit Off
L Saturated Off
Sample Application Timing Chart
Sample application timing chart
1Connect a DC motor (RL=RΩ) between OUT1 and OUT2, and with the RD pin pulled up, input a forward rotation signal
(IN1 = high, IN2 = low).
Because the output is used in the saturated state at startup, set the DEL input to low.
2The DC motor starts up, and the startup current (IST =V
M
/R) flows to the motor.
3The DC motor rotates in the normal state. At this point, set the DEL input to high.
4If the DC motor locks, the motor current IMincreases to the point of Ilimit (= VLIR/(10Rf)), the output current limiter operates
to limit the output current. At the same time, RD is output low from the set current detection circuit.
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No.4385-4/6
Reference voltage (Vref)
The Vref output is linked to the input; if either IN1 or IN2 is high, the reference voltage is output.
Output current limiter
The schematic for the output current limiter is shown below.
The output set current is set according to the reference voltage VLIR applied to the LIR pin. When VLIR is applied, 1/10 of that
voltage is generated at both ends of RSin the diagram; this voltage is input on the positive (+) side of the current setting
amplifier.
The motor current IMgenerates voltage equal to (IM×Rf) at both ends of the external resistor Rf. This voltage is input to the
negative (–) side of the same amplifier, and the differential amplifier functions and the output transistors are driven so that these
inputs become equal.
The set current value in this instance is determined by the following equation:
Ilimit =V
LIR/(10Rf) [A]
Set current detector
(1) When DEL = high
If the motor current IMhas not reached the set current Ilimit, the input voltage on the negative (–) side of the amplifier is
greater than the input voltage on the positive (+) side. As a result, the drive current increases and the output PNP transistors
reach the saturation state. If this state is detected, the detection signal is sent to the set current detector, and the RD output
goes high.
If the motor current IMreaches the set current Ilimit, the output PNP transistor enters the controlled state, and the RD output
goes low.
(2) When DEL = low
Because the operation of the current setting amplifier is cancelled when a low signal is input to the DEL pin, the output PNP
transistors reach the saturation state and the RD output goes high, just as in the case described above.
The following table summarizes the states described above.
DEL OUT RD
Hlimit L
Non-limit (saturated) H
L Saturated H
Output Current Limiter and Set Current Detector Block Diagram
Set current
detector
LB1843V
No.4385-5/6
No products described or contained herein are intended for use in surgical implants, life-support systems,
aerospace equipment, nuclear power control systems, vehicles, disaster/crime-prevention equipment and the like,
the failure of which may directly or indirectly cause injury, death or property loss.
Anyone purchasing any products described or contained herein for an above-mentioned use shall:
1Accept full responsibility and indemnify and defend SANYO ELECTRIC CO., LTD., its affiliates, subsidiaries and
distributors and all their officers and employees, jointly and severally, against any and all claims and litigation
and all damages, cost and expenses associated with such use:
2Not impose any responsibility for any fault or negligence which may be cited in any such claim or litigation on
SANYO ELECTRIC CO., LTD., its affiliates, subsidiaries and distributors or any of their officers and employees
jointly or severally.
Information (including circuit diagrams and circuit parameters) herein is for example only; it is not guaranteed for
volume production. SANYO believes information herein is accurate and reliable, but no guarantees are made or
implied regarding its use or any infringements of intellectual property rights or other rights of third parties.
This catalog provides information as of October, 1996. Specifications and information herein are subject to change without notice.
ICC –V
CC
Current drain, ICC –mA
R
f
= 0.5 Ω, no load
Brake
Bidirec-
tional
Supply voltage, VCC –V
I
IN –V
IN
Input current, IIN –µA
Input voltage, VIN –V
I
limit –V
LIR
Set output current, Ilimit –mA
V
LIR –V
I
limit –V
CC
Set output current, Ilimit –mA
Supply voltage, VCC –V
V
O
(sat) – IO
Output saturation voltage, VO(sat) – V
Output current, IO–mA
V
O
(sat) – Ta
Output saturation voltage, VO(sat) – V
Ambient temperature, Ta – °C
LB1843V
No.4385-6/6
