TPS92690EVM Boost Evaluation Module
User's Guide
Literature Number: SLVU803
December 2012
Contents
1 N-Channel Controller for Dimmable LED Drives with Low-Side Current Sense ........................... 4
1.1 Introduction .................................................................................................................. 4
2 Detailed Description ............................................................................................................ 5
2.1 Description ................................................................................................................... 5
2.1.1 Typical Applications ................................................................................................ 5
2.1.2 Features ............................................................................................................. 5
3 Electrical Performance Specifications ................................................................................... 7
4 Schematic .......................................................................................................................... 8
5 Performance Data and Typical Characteristic Curves .............................................................. 9
5.1 Efficiency ..................................................................................................................... 9
5.2 Line Regulation .............................................................................................................. 9
5.3 Switch Node Voltage and LED Current Ripple ........................................................................ 10
5.4 PWM Dimming ............................................................................................................. 10
5.5 Start-up and Shut-down Response ..................................................................................... 11
5.6 Thermal Performance ..................................................................................................... 12
6 TPS92690EVM PCB layout .................................................................................................. 13
A Bill of Materials ................................................................................................................. 14
2Contents SLVU803–December 2012
Submit Documentation Feedback
Copyright © 2012, Texas Instruments Incorporated
www.ti.com
List of Figures
4-1. TPS92690EVM Schematic ................................................................................................ 8
5-1. Efficiency..................................................................................................................... 9
5-2. Line Regulation.............................................................................................................. 9
5-3. Switching and LED Current .............................................................................................. 10
5-4. PWM Dimming, fPWM = 200 Hz, Duty Cycle = 50%.................................................................... 10
5-5. PWM Dimming, fPWM = 200 Hz, Duty Cycle = 5% ..................................................................... 10
5-6. PWM Dimming, fPWM = 200 Hz, Duty Cycle = 95%.................................................................... 11
5-7. Start-up Waveform ........................................................................................................ 11
5-8. Shut-down Waveform..................................................................................................... 11
5-9. Top Thermal Performance ............................................................................................... 12
5-10. Bottom Thermal Performance ........................................................................................... 12
6-1. Top Layer and Top Overlay (Top View)................................................................................ 13
6-2. Bottom Layer and Bottom Overlay (Bottom View) .................................................................... 13
List of Tables
3-1. TPS92690EVM Electrical Performance Specifications ................................................................ 7
A-1. The TPS92690EVM Components List (According to the Schematic Shown in Figure 4-1)..................... 14
3
SLVU803–December 2012 List of Figures
Submit Documentation Feedback Copyright © 2012, Texas Instruments Incorporated
Chapter 1
SLVU803–December 2012
N-Channel Controller for Dimmable
LED Drives with Low-Side Current Sense
1.1 Introduction
The TPS92690EVM evaluation module (EVM) helps designers evaluate the operation and performance of
the TPS92690 DC-DC N-channel MOSFET controller. The TPS92690 is designed to drive high-brightness
light emitting diodes (LEDs) and features a wide input voltage range (4.5 V to 75 V), analog current adjust,
PWM dimming, low-power shutdown, a precision reference, switching frequency synchronization, and low
side LED current sense.
4N-Channel Controller for Dimmable LED Drives with Low-Side Current Sense SLVU803–December 2012
Submit Documentation Feedback
Copyright © 2012, Texas Instruments Incorporated
Chapter 2
SLVU803–December 2012
Detailed Description
2.1 Description
The TPS92690EVM provides a high-brightness LED driver based on the TPS92690 configured as a boost
(step-up) regulator. It is designed to operate with an input voltage in the range of 8 V to 19 V with a 12-V
nominal input voltage. This input voltage range is typical for automotive applications and common for
many off the shelf AC-DC sources. The EVM is set up for a default output current of 500 mA with an
output voltage range of 20 V to 35 V or approximately 7 to 10 LEDs, depending on the forward voltage of
each.
2.1.1 Typical Applications
This converter design describes an application of the TPS92690 as an LED driver with the specifications
listed below. For applications with a different input voltage range or different output voltage range, refer to
the TPS92690 datasheet.
2.1.2 Features
2.1.2.1 Connector Description
This section describes the connectors and test points on the EVM and how to properly connect, setup,
and use the TPS92690EVM.
2.1.2.1.1 J1, J4, J10 (VIN, GND)
These two test points and the screw down connector are for the input voltage supply to the converter. The
leads to the input supply should be twisted and kept as short as possible to minimize voltage drop,
inductance, and EMI transmission. Additional bulk capacitance between VIN and GND may be desirable if
the supply leads are greater than twelve inches, particularly if pulse width modulation (PWM) dimming will
be used. If using the screw down connector J1, pin 1 is VIN and pin 2 is GND.
2.1.2.1.2 J2, J3, J8 (LED+, LED-)
Connect the LED string between J3 and J8 with the anode of one end connected to LED+ and the
cathode of the other end connected to LED-. Alternatively, the screw down connector J2 may be used. Pin
1 of J2 is LED- and pin 2 is LED+.
2.1.2.1.3 GND
An additional ground test point is provided for ease of use. Ground leads for voltage probes, function
generators, or low power analog supplies may be connected to either GND test point.
2.1.2.1.4 PWM DIM
This test point is connected through a blocking diode to the nDIM pin of the TPS92690. Pulling this test
point to ground will disable switching and turn the LEDs off. A square wave with a low level of ground and
a high level greater than the nDIM pin threshold (greater than 1.24 V and up to 30 V) may be applied to
this test point to dim using PWM. The average LED current is approximately equal to the positive duty
cycle of the PWM signal multiplied by the steady state LED current. The PWM dimming frequency should
be between 120 Hz and 1 kHz to maintain the best linearity.
5
SLVU803–December 2012 Detailed Description
Submit Documentation Feedback Copyright © 2012, Texas Instruments Incorporated
Description
www.ti.com
2.1.2.1.5 SYNC
This test point connects directly to the SYNC pin of the TPS92690. Applying a square wave to this test
point with a low level of ground and a high level between 2.5 V and 5 V synchronizes the switching
frequency of the TPS92690 with the applied square wave. The falling edge of the applied square wave
triggers an on time of the power FET. The synchronizing frequency should be at least 10% higher than the
native switching frequency set by the resistor from the RT pin to ground.
2.1.2.1.6 SS/SD
The SS/SD test point can be used to disable the device and place it into low power shutdown. It may also
be used for monitoring the soft-start function with a voltage probe. Pull this test point to ground to disable
the circuit.
2.1.2.1.7 IADJ
The IADJ test point is connected directly to the IADJ pin of the TPS92690. A resistor divider from VREF
sets the default level of the IADJ pin to 500 mV which results in a default LED current of 500 mA. A low
power voltage supply can be connected to the IADJ test point to either increase or decrease the LED
current. This provides the analog dimming functionality of the TPS92690.
2.1.2.1.8 SW
This test point is strictly for monitoring the switching waveform. It is connected directly to the drain of the
power switching FET.
6Detailed Description SLVU803–December 2012
Submit Documentation Feedback
Copyright © 2012, Texas Instruments Incorporated
Chapter 3
SLVU803–December 2012
Electrical Performance Specifications
Table 3-1. TPS92690EVM Electrical Performance Specifications
PARAMETER TEST CONDITIONS MIN TYP MAX UNITS
Input Characteristics
Voltage range 8 12 19 V
Maximum input current At IOUT = 500 mA 2.4 A
Input rising 7.8 V
Undervoltage lockout level Input falling 5.5 V
Output Characteristics
Output voltage, VOUT At IOUT = 500 mA 20 35 V
Output load current, IOUT IADJ = 0 V to 1 V 2 500 1000 mA
Output current regulation Line Regulation: Input voltage = 8 V to 19 V 0.5 %
Output current ripple At IOUT = 500 mA 25 mApp
Overvoltage protection level Output rising 41.3 V
Systems Characteristics
Switching frequency 420 kHz
Efficiency Input voltage = 12 V, Load = 10 LEDs at 500 mA 94 %
PWM Dim frequency 120 1000 Hz
7
SLVU803–December 2012 Electrical Performance Specifications
Submit Documentation Feedback Copyright © 2012, Texas Instruments Incorporated
490
494
498
502
506
510
8 10 12 14 16 18
Input Voltage (V)
Output Current (mA)
10 LEDs
G001
90
92
94
96
98
100
10 12 14 16 18
Input Voltage (V)
Efficiency (%)
10 LEDs @ 500mA
G000
Chapter 5
SLVU803–December 2012
Performance Data and Typical Characteristic Curves
Figure 5-1 through Figure 5-8 show typical performance curves for the TPS92690EVM.
5.1 Efficiency
Figure 5-1. Efficiency
5.2 Line Regulation
Figure 5-2. Line Regulation
9
SLVU803–December 2012 Performance Data and Typical Characteristic Curves
Submit Documentation Feedback Copyright © 2012, Texas Instruments Incorporated
PWM DIM
Switching Node
LED Current
PWM DIM
Switching Node
LED Current
Switching Node
LED Current
Switch Node Voltage and LED Current Ripple
www.ti.com
5.3 Switch Node Voltage and LED Current Ripple
Figure 5-3. Switching and LED Current
5.4 PWM Dimming
Figure 5-4. PWM Dimming, fPWM = 200 Hz, Duty Cycle = 50%
Figure 5-5. PWM Dimming, fPWM = 200 Hz, Duty Cycle = 5%
10 Performance Data and Typical Characteristic Curves SLVU803–December 2012
Submit Documentation Feedback
Copyright © 2012, Texas Instruments Incorporated
SS/SD
Switching Node
LED Current
SS/SD
Switching Node
LED Current
PWM DIM
Switching Node
LED Current
www.ti.com
Start-up and Shut-down Response
Figure 5-6. PWM Dimming, fPWM = 200 Hz, Duty Cycle = 95%
5.5 Start-up and Shut-down Response
Figure 5-7. Start-up Waveform
Figure 5-8. Shut-down Waveform
11
SLVU803–December 2012 Performance Data and Typical Characteristic Curves
Submit Documentation Feedback Copyright © 2012, Texas Instruments Incorporated
Thermal Performance
www.ti.com
5.6 Thermal Performance
Figure 5-9 and Figure 5-10 show the steady state thermal performance of the EVM under the following
conditions:
• Load of 10 LEDs
• ILED = 500 mA
• VIN = 12 VDC
Figure 5-9. Top Thermal Performance
Figure 5-10. Bottom Thermal Performance
12 Performance Data and Typical Characteristic Curves SLVU803–December 2012
Submit Documentation Feedback
Copyright © 2012, Texas Instruments Incorporated
Chapter 6
SLVU803–December 2012
TPS92690EVM PCB layout
Figure 6-1 and Figure 6-2 show the design of the TPS92690EVM printed circuit board.
Figure 6-1. Top Layer and Top Overlay (Top View)
Figure 6-2. Bottom Layer and Bottom Overlay (Bottom View)
13
SLVU803–December 2012 TPS92690EVM PCB layout
Submit Documentation Feedback Copyright © 2012, Texas Instruments Incorporated
Appendix A
SLVU803–December 2012
Bill of Materials
Table A-1. The TPS92690EVM Components List
(According to the Schematic Shown in Figure 4-1)
REFERENCE QTY VALUE DESCRIPTION SIZE MFR PART NUMBER
DESIGNATOR
DC-DC Controller with Low Side FET
U1 1 eTSSOP-16 TI TPS92690PWP
and Low Side Current Sense
C3 1 0.1 µF Capacitor, Ceramic, 100 V, X7R 0805 Kemet C0805C104K1RACTU
C5, C6 2 4.7 µF Capacitor, Ceramic, 50 V, X7R 2220 MuRata GRM55ER71H475MA01L
C7, C8 2 4.7 µF Capacitor, Ceramic, 50 V, X7R 1210 MuRata GRM32ER71H475KA88L
C9 1 2.2 µF Capacitor, Ceramic, 16 V, X7R 0805 MuRata GRM21BR71C225KA12L
C10, C11 2 2.2 µF Capacitor, Ceramic, 50 V, X7R 1812 TDK C4532X7R1H225M
C12 1 0.047 µF Capacitor, Ceramic, 50 V, X8R 0603 TDK C1608X8R1H473K
C13, C15, C17 3 0.1 µF Capacitor, Ceramic, 50 V, X7R 0805 MuRata GRM21BR71H104KA01L
C14 1 0.1 µF Capacitor, Ceramic, 25 V, X7R 0603 MuRata GRM188R71E104KA01D
C16 1 1000 pF Capacitor, Ceramic, 50 V, X7R 0805 Kemet C0805C102K5RACTU
D1 1 Diode, Schottky, 30 V, 0. 2 A SOD-123 ON Semi MMSD301T1G
D2 1 Diode, Schottky, 60 V, 2 A SMB ON Semi SS26T3G
L1 1 22 µH Inductor, SMT, 6 A 12 mm x 12 mm Coilcraft MSS1278-223MLD
Q7 1 MOSFET, N-channel, 100 V, 32 A D-PAK Fairchild FDD3682
R1 1 53.6 kΩResistor, Chip, 1/8 W, 1% 0805 Std Std
R2, R4 2 10 kΩResistor, Chip, 1/8 W, 1% 0805 Std Std
R3 1 56.2 kΩResistor, Chip, 1/8 W, 1% 0805 Std Std
R5, R8, R9 3 100 kΩResistor, Chip, 1/8 W, 1% 0805 Std Std
R6 1 0.1 ΩResistor, Chip, 1/2 W, 1% 2010 Dale WSL2010R1000FEA
R7 1 26.1 kΩResistor, Chip, 1/8 W, 1% 0805 Std Std
R10 1 909 kΩResistor, Chip, 1/8 W, 1% 0805 Std Std
R11, R17 2 0 ΩResistor, Chip, 1/8 W, 1% 0805 Std Std
R12 1 1.74 kΩResistor, Chip, 1/8 W, 1% 0805 Std Std
R13 1 1 kΩResistor, Chip, 1/8 W, 1% 0805 Std Std
R14 1 47 ΩResistor, Chip, 1/10 W, 5% 0603 Std Std
R16 1 0 ΩResistor, Chip, 1/10 W, 5% 0603 Std Std
R19 1 0 ΩResistor, Chip, 1 W, 1% 2512 Dale CRCW25120000Z0EG
R21 1 10 kΩResistor, Chip, 1/10 W, 5% 0603 Std Std
C1 0 DNP
C4 0 DNP
R15 0 DNP
R18 0 DNP
R20 0 DNP
14 Bill of Materials SLVU803–December 2012
Submit Documentation Feedback
Copyright © 2012, Texas Instruments Incorporated
IMPORTANT NOTICE
Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, enhancements, improvements and other
changes to its semiconductor products and services per JESD46, latest issue, and to discontinue any product or service per JESD48, latest
issue. Buyers should obtain the latest relevant information before placing orders and should verify that such information is current and
complete. All semiconductor products (also referred to herein as “components”) are sold subject to TI’s terms and conditions of sale
supplied at the time of order acknowledgment.
TI warrants performance of its components to the specifications applicable at the time of sale, in accordance with the warranty in TI’s terms
and conditions of sale of semiconductor products. Testing and other quality control techniques are used to the extent TI deems necessary
to support this warranty. Except where mandated by applicable law, testing of all parameters of each component is not necessarily
performed.
TI assumes no liability for applications assistance or the design of Buyers’ products. Buyers are responsible for their products and
applications using TI components. To minimize the risks associated with Buyers’ products and applications, Buyers should provide
adequate design and operating safeguards.
TI does not warrant or represent that any license, either express or implied, is granted under any patent right, copyright, mask work right, or
other intellectual property right relating to any combination, machine, or process in which TI components or services are used. Information
published by TI regarding third-party products or services does not constitute a license to use such products or services or a warranty or
endorsement thereof. Use of such information may require a license from a third party under the patents or other intellectual property of the
third party, or a license from TI under the patents or other intellectual property of TI.
Reproduction of significant portions of TI information in TI data books or data sheets is permissible only if reproduction is without alteration
and is accompanied by all associated warranties, conditions, limitations, and notices. TI is not responsible or liable for such altered
documentation. Information of third parties may be subject to additional restrictions.
Resale of TI components or services with statements different from or beyond the parameters stated by TI for that component or service
voids all express and any implied warranties for the associated TI component or service and is an unfair and deceptive business practice.
TI is not responsible or liable for any such statements.
Buyer acknowledges and agrees that it is solely responsible for compliance with all legal, regulatory and safety-related requirements
concerning its products, and any use of TI components in its applications, notwithstanding any applications-related information or support
that may be provided by TI. Buyer represents and agrees that it has all the necessary expertise to create and implement safeguards which
anticipate dangerous consequences of failures, monitor failures and their consequences, lessen the likelihood of failures that might cause
harm and take appropriate remedial actions. Buyer will fully indemnify TI and its representatives against any damages arising out of the use
of any TI components in safety-critical applications.
In some cases, TI components may be promoted specifically to facilitate safety-related applications. With such components, TI’s goal is to
help enable customers to design and create their own end-product solutions that meet applicable functional safety standards and
requirements. Nonetheless, such components are subject to these terms.
No TI components are authorized for use in FDA Class III (or similar life-critical medical equipment) unless authorized officers of the parties
have executed a special agreement specifically governing such use.
Only those TI components which TI has specifically designated as military grade or “enhanced plastic” are designed and intended for use in
military/aerospace applications or environments. Buyer acknowledges and agrees that any military or aerospace use of TI components
which have not been so designated is solely at the Buyer's risk, and that Buyer is solely responsible for compliance with all legal and
regulatory requirements in connection with such use.
TI has specifically designated certain components as meeting ISO/TS16949 requirements, mainly for automotive use. In any case of use of
non-designated products, TI will not be responsible for any failure to meet ISO/TS16949.
Products Applications
Audio www.ti.com/audio Automotive and Transportation www.ti.com/automotive
Amplifiers amplifier.ti.com Communications and Telecom www.ti.com/communications
Data Converters dataconverter.ti.com Computers and Peripherals www.ti.com/computers
DLP® Products www.dlp.com Consumer Electronics www.ti.com/consumer-apps
DSP dsp.ti.com Energy and Lighting www.ti.com/energy
Clocks and Timers www.ti.com/clocks Industrial www.ti.com/industrial
Interface interface.ti.com Medical www.ti.com/medical
Logic logic.ti.com Security www.ti.com/security
Power Mgmt power.ti.com Space, Avionics and Defense www.ti.com/space-avionics-defense
Microcontrollers microcontroller.ti.com Video and Imaging www.ti.com/video
RFID www.ti-rfid.com
OMAP Applications Processors www.ti.com/omap TI E2E Community e2e.ti.com
Wireless Connectivity www.ti.com/wirelessconnectivity
Mailing Address: Texas Instruments, Post Office Box 655303, Dallas, Texas 75265
Copyright © 2012, Texas Instruments Incorporated
