Description

The A8512 is a multi-output WLED/RGB driver for backlighting LCD monitors and televisions. It integrates a boost controller to drive external MOSFET, and six internal current-sinks. The boost converter operates in constant frequency (programmable) current mode control. PWM dimming allows LED currents to be controlled in 500:1 ratio. The LED sink current is set by an external R_ISET resistor (see chart below). More than one LED sinks can be combined together to achieve even higher current per LED string. Multiple A8512s can be connected in parallel, with one master controller controlling the boost stage, and up to five slave controllers, which act as LED sinks. This allows up to 36 LED strings to be powered by just one boost converter.

Specifications and features

▪ Six integrated high current sinks
▪ Fixed frequency current mode control with integrated gate driver
▪ 300 kHz to 1 MHz adjustable switching frequency
▪ Controlled startup using options of Enable, PWM signal, or battery voltage ramp
▪ Parallel operation with one boost controller (master) and up to five slave controllers
▪ Active current sharing between LED strings for ±0.6% accuracy and matching
▪ No audible MLCC noise during PWM dimming
▪ Adjustable overvoltage protection (OVP)
▪ Open or shorted LED string protection
▪ Overtemperature, cycle-by-cycle current limit, and undervoltage protection
▪ SOIC 24-pin package for easy single-side PCB manufacturing, or TSSOP 24-pin and QFN 28-contact packages with exposed thermal pad for better thermal performance

Application Scenarios

The A8512 is designed specifically for backlighting LCD monitors and televisions. It is suitable for applications requiring multiple LED strings to be powered by a single boost converter.

Comparison

Advantages:

• Integrates a boost controller for driving external MOSFET
• Allows up to 36 LED strings to be powered by one boost converter
• Active current sharing between LED strings for ±0.6% accuracy and matching
• No audible MLCC noise during PWM dimming
• Adjustable overvoltage protection (OVP)
• Open or shorted LED string protection
• Overtemperature, cycle-by-cycle current limit, and undervoltage protection

Disadvantages: None