AEC-Q100 Synchronous 60V Buck-Boost LED driver Controller for LED StringsJuly 11, 2019 by Scott McMahan
The MAX25600 from Maxim Integrated is a synchronous 4-switch buck-boost LED driver controller. The controller regulates the LED current for LED string voltages from 0V to 60V. The MAX25600 can be employed as a seamless buck-boost LED driver for applications that require an efficient buck-boost LED driver with synchronous rectification.
The MAX25600 is suitable for high-power applications that need a current source with PWM dimming capability. Typical applications include automotive exterior lighting as well as general, commercial, and industrial lighting. (See image above of simplified typical application circuit). The device offers a seamless transition between buck, boost, and buck-boost modes depending on the ratio of input to output voltage.
A fault flag indicates an open LED, shorted LED, or thermal shutdown conditions. The device utilizes Maxim's proprietary average-current-mode control strategy and allows adjustable 200kHz to 700kHz fixed-frequency operation.
In addition, it adds ±6% triangular spread spectrum internally to the oscillator to enhance EMI performance.
The MAX25600 delivers both analog and digital PWM dimming and features a built-in analog PWM dimming at a dimming frequency of 200Hz.
Adjustable soft-start limits the current peaks and voltage overshoots at startup. The MAX25600 integrates a high-side p-channel dimming MOSFET driver for PWM dimming that requires fast rising and falling edges of the LED current. It also features robust output with open and short protection. It is AEC qualified and is suitable for automotive applications.
- Automotive Ready: AEC-Q100 Qualified
- Integration Minimizes BOM for High-Brightness LED Driver, Saving
- Space and Reducing Cost
- Wide Input-Voltage Range from 5V to 60V
- H-Bridge Single Inductor Buck-Boost Architecture
- Constant-Current and Constant-Voltage Regulation
- 28-pin TSSOP with EP Pad and 28-pin(5mm x 5mm) TQFN with EP Pad Packages
- Wide Dimming Ratio allows High Contrast Ratio
- Analog and PWM Dimming
- Flicker-Free PWM Dimming with Spread Spectrum
- Integrated pMOS Dimming FET Gate Driver
- 200Hz On-Board Ramp Simplifies PWM Dimming
- Protection Features and Wide Temperature Range Increase System Reliability
- Short Circuit, Over-Voltage, and Thermal Protection
- LED Current Monitor and Input Current Limiter
- -40°C to +125°C Operating Junction-Temperature Range