The reference design launched by WPG is a dual-string LED light-emitting diode (LED) driver that uses an op-amp-based circuit to balance the current in two LED strings. The operational amplifier circuit detects the reference string. The current, and use the feedback of the mirror string to bias the MOSFETs that regulate the current between the strings.
This solution uses a boosted TPS92692-Q1 multi-topology LED driver to drive the LEDs. The TPS92692-Q1 has spread-spectrum frequency modulation for electromagnetic interference (EMI) performance, analog current regulation and internal pulse width modulation (PWM) dimming. This design includes the use of the LMT87-Q1's adjustable linear thermal foldback analog temperature sensor and current limit to prevent the image string from opening the circuit. The design also has two brightness modes: one is the full brightness mode and the other is Reduced brightness PWM dimming mode.
Product Features - Two-string current balancing using a single LED driver; - Passing CISPR25 Class-5 conduction and radiated emission test; - PWM dimming in two brightness modes; - Current limit; - Operation by cold crank; - No need for micro-control Unit (MCU)
This module (EVM) helps designers evaluate the operation and performance of the TPS92692-Q1 and TPS92692 high-precision LED controllers designed for automotive lighting and general lighting applications.
The TPS92692EVM-880 uses the TPS92692-Q1 (AEC Q100) device; however, for general lighting and other non-automotive applications, the TPS92692 uses the same package and pin configuration with the same performance characteristics.
The TPS92692-Q1 device implements a fixed-frequency peak current-mode control technique with programmable switching frequency, slope compensation, and startup timing. It integrates a low-offset rail-to-rail current sense amplifier that can measure directly from an output voltage range of 0V to 65V. LED current. Other features include wide input voltage range (4.5V to 65V), spread spectrum frequency modulation, analog to PWM converter circuit, direct PWM dimming, analog dimming, adjustable switching frequency, input undervoltage protection, output Overvoltage protection and switch cycle-by-cycle current limiting. Based on the output LED stack voltage, the controller can be used to implement a series of LED driver topologies including boost, buck-boost (boost to battery), SEPIC and flyback .
Product application - car daytime running lights; - car front lighting; - car taillights and brake lights.