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Holtek HT7955电视WLED背光驱动解决方案 消费电子 免费猫

发布时间:2020-02-17 12:29:10 阅读: 来源:仓顶除尘器厂家

Holtek HT7955电视WLED背光驱动解决方案 - 消费电子 - 电子工程网

The HT7955 is a high efficiency DC-DC controller drives a number of WLEDs connected in series/ parallel configuration and has a wide input voltage range from 10V to 26V, and adjustable 60mA to 80mA WLED current by external resistor. In total, the device can support up to 80 WLED.

In addition, six current sink regulators provide ±2.5% high precision current matching between strings. The brightness can be adjusted by external PWM up to 2kHz. Once an open/short string is detected, the string is disabled while other strings operate normally.

Other protecting includes soft-start, under voltage lockout, programmable over voltage protection, WLED current limit, switch current limit and thermal shutdown.

The HT7955 is packaged with a tiny footprint package of 48-Pin 7x7x1.0mm TQFP-EP package.

HT7955主要特性:

Allowable max input voltage: 26V

Built-in Power MOSFET

Output voltage up to 40V driving 10 series LEDs – LED Vf(max)=3.5V per string – absolute max rating up to 44V

Channel Phase Shift PWM Dimming

Direct PWM Dimming without Phase Shift

Operate up to 11 strings LED at Vf(max.)=3.3V condition

Low string feedback voltage: 0.5V at 80mA LED current

Switching frequency: 200kHz/400kHz

8-string constant current output

LED current adjustable from 60mA to 80mA

±2.5% current matching between strings

Dimming control using PWM

1% minimum dimming duty-cycle at 2kHz

Built- in Soft start

LED failure detection: open and short circuit

Capacitor type: ceramic

•rotection: OVP, OTP, UVLO, LX current limit

HT7955应用:

LED backlights for LCD monitor and LCD TV

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