TI公司的tps92691/-Q1是具有轨到轨电流检测放大器的多种拓扑LED驱动器,输入电压4.5 V 到 65 V,输出电压2 V 到65 V,在25°C - 140°C温度范围优于±3%的LED电流精度,可编开关频率和软起动与斜率补偿,主要用在紧急照明和外部照明如头灯.本文介绍了TPS92691/-Q1主要特性,框图和几种应用电路,以及汽车照明TIDA-01183参考设计主要特性和指标,框图,电路图,材料清单和PCB设计图.

Precision PWM Dimming LED Driver Reference Design for Automotive Lighting

(ACTIVE) TIDA-01183

The TPS92691/-Q1 is a versatile LED controller that can support a range of step-up or step-down driver topologies. The device implements a fixed-frequency peak current mode control technique with programmable switching frequency, slope compensation, and soft-start timing. It incorporates a high voltage (65-V) rail-to-rail current sense amplifier that can directly measure LED current using either a high-side or a low-side series sense resistor. The amplifier is designed to achieve low input offset voltage and attain better than ±3% LED current accuracy over junction temperature range of 25°C to 140°C and output common-mode voltage range of 0 to 60 V.

LED current can be independently modulated using either analog or PWM dimming techniques. Linear analog dimming response with 15:1 range is obtained by varying the voltage from 140 mV to 2.25 V across the high impedance analog adjust (IADJ) input. PWM dimming of LED current is achieved by modulating the PWM input pin with the desired duty cycle and frequency. Optional DDRV gate driver output can be used to enable series FET dimming functionality to get over 1000:1 contrast ratio.

The TPS92691/-Q1 supports continuous LED status check through the current monitor (IMON) output. This allows for LED short circuit or open circuit detection and protection. Additional fault protection features include VCC UVLO, output OVP, switch cycle-by-cycle current limit, and thermal protection.

TPS92691/-Q1主要特性:

Wide Input Voltage: 4.5 V to 65 V

Wide Output Voltage Range: 2 V to 65 V

Low Input Offset Rail-to-Rail Current Sense Amplifier

Better than ±3% LED Current Accuracy over 25°C to 140°C Junction Temperature Range

Compatible With High-Side and Low-Side Current Sense Implementations

High-Impedance Analog LED Current Adjust Input (IADJ) With over 15:1 Contrast Ratio

Over 1000:1 Series FET PWM Dimming Ratio With Integrated Series N-Channel Dim Driver Interface

Continuous LED Current Monitor Output for System Fault Detection and Diagnoses

Programmable Switching Frequency With External Clock Synchronization Capability

Programmable Soft-Start and Slope Compensation

Comprehensive Fault Protection Circuitry Including VCC Undervoltage Lockout (UVLO), Output Overvoltage Protection (OVP), Cycle-by-Cycle Switch Current Limit, and Thermal Protection

TPS92691-Q1: Automotive Q100 Grade 1 Qualified

TPS92691/-Q1应用:

Exit, Emergency Lighting

Exterior Lighting - Headlight

图1. TPS92691/-Q1框图

图2. TPS92691/-Q1升压LED驱动器应用电路图

图3. TPS92691/-Q1SEPIC LED驱动器应用电路图

图4. TPS92691/-Q1降压-升压LED驱动器应用电路图

图5. TPS92691/-Q1降压LED驱动器应用电路图

图6. TPS92691/-Q1带高边电流检测的升压LED驱动器

图7. TPS92691/-Q1降压-升压LED驱动器

汽车照明TIDA-01183参考设计

The TIDA-01183 TI Design details a solution on how to use pulse width modulation (PWM) to dim an automotive headlight or tail light with a precision of better than 2% duty cycle without the necessity of using a micro controller. This allows the design to be very cost competitive. Devices used in this design are the TPS92691-Q1 multi-topology LED Driver in boost and boost to battery configuration controlling the LEDs. The TLC555-Q1 LinCMOS timer, together with the OPA2377-Q1 operational amplifier, measure and generate an accurate PWM signal by applying a feedback loop and a precision shunt regulator for setting the duty cycle accurately. The designs input stage is EMI/EMC filtered and can be directly supplied by the cars battery.

TIDA-01183参考设计主要特性:

Precisioin PWM dimming

Efficiency-optimized design

Operation through cold crank

Load dump tolerant

TIDA-01183参考设计电特性表:

图8. TIDA-01183参考设计框图

图9. TIDA-01183参考设计3D外形图

图10. TIDA-01183参考设计和LED子板外形图

图11. TIDA-01183参考设计电路图(1)

图12. TIDA-01183参考设计电路图(2)

TIDA-01183参考设计材料清单:

图13. TIDA-01183参考设计PCB设计图(1)

图14. TIDA-01183参考设计PCB设计图(2)

图15. TIDA-01183参考设计PCB设计图(3)

图16. TIDA-01183参考设计PCB设计图(4)

图17. TIDA-01183参考设计PCB设计图(5)

图18. TIDA-01183参考设计PCB设计图(6)

图19. TIDA-01183参考设计PCB外形尺寸图