ISSI IS32LT3958 | Demoboard IS32LT3958 BUCKBOOST EVALUATION BOARD

Description

The IS32LT3958 is a current mode PWM controller designed to drive a low side external NMOS FET for wide input/output voltage range and high LED current applications. An external resistor senses the high side output current of the LED string. A high side sense is the most flexible current sensing scheme, since it functions in either boost or buck-boost mode configurations. The controller can be configured with an external resistor to operate between 100kHz~1MHz frequency resulting in small external inductor and capacitors while maintaining high efficiency. A single capacitor is all that is required to set the spread spectrum dither frequency to reduce the radiated peak emission and optimize the system EMI performance.

Features

• Wide high voltage input range: 5V to 70V
• Supports boost, buck-boost, SEPIC and buck topology
• Supports either analog, internal PWM dimming or external PWM dimming
• Stand-alone dual brightness output by internal PWM dimming
• Integrated PWM generator
• 100Hz~1kHz adjustable PWM frequency
• 5%~100% adjustable PWM duty cycle
• Excellent analog dimming capability
• Two analog dimming pins
• LED binning capability
• LED over temperature current rolloff
• Externally programmable input undervoltagelockout
• ±2.8% output current accuracy over -40°C ~ +150°C temperature
• Adjustable operating frequency range of 100kHz~1MHz
• Programmable soft start to avoid inrush current
• EMI reduction capabilities
• Programmable spread spectrum function
• Operating frequency synchronization with external clock source
• Fault protection with reporting:
• VCC under voltage lockout (not reported)
• Programmable output overvoltage protection
• Output short circuit protection
• RT/SYNC pin short protection
• VDD pin short protection
• VDD under voltage lockout (not reported)
• Over temperature protection
• RoHS & Halogen-Free Compliance
• TSCA Compliance
• AEC-Q100 Qualified with Temperature Grade 1: -40°C to 125°C

Typical applications

• LED load (7~10 LEDs in series/1A)
• 9V~16V, 6A DC power supply

More information

• Datasheet
• IC product information