描述 Description

The MP4657B is a single-stage, flyback, 4-string LED driver and system voltage (VSYS) controller for LED backlighting on the secondary side. It controls the flyback power stage and an external N-channel MOSFET to regulate the system supply voltage and LED current loop with integrated 4-string LED current balancing. With a 4V to 16V input voltage (VIN), the MP4657B outputs a direct driving signal to control the N-channel MOSFET that regulates the system supply voltage. It also outputs a compensation signal to control the primary-side flyback (or other power stage) via an optocoupler.

The device supports pulse-width modulation (PWM) dimming and analog dimming to the LED current (ILED) via the ADIMP/PWM pin. For analog dimming, apply a pulse signal with a >5kHz frequency to this pin. For PWM dimming, apply a pulse signal with a <5kHz frequency.

The MP4657B uses an individual control method for ILED and VSYS. If the PWM signal is effective, then the LED current loop is regulated via the flyback power stage, and VSYS is further regulated by the N-channel MOSFET. Soft switching of the N-channel MOSFET reduces voltage spikes. If the PWM signal is ineffective, then the flyback power stage controls VSYS.

Full protection features include LED open protection, LED short protection, LEDx pin short-to-ground protection, over-voltage protection (OVP), feedback (FB) open-loop protection, and thermal shutdown. The MP4657B is available in an SOIC-16 package.

特性 Features

? Single-Stage Flyback for Highly Efficient LED Current (ILED) and System Voltage (VSYS) Regulation
? Individual Control Methods for the LED Driver Stage and VSYS Stage
? 4V to 16V Input Voltage (VIN)
? 80V, 4-String LED Current Balancing
? 5% VSYS Accuracy
? 5% ILED Accuracy and 2% LED Current Balancing
? Low LEDx Regulation Voltage for High Efficiency
? Fast Dynamic Control with Fast Response
? System Input Over-Voltage Protection (OVP)
? System Input Short Protection
? LED Open Protection
? LED Short Protection
? LEDx Pin Short-to-Ground Protection
? Feedback (FB) Open Loop Protection for VSYS
? Soft Switching for External N-Channel MOSFET
? Thermal Shutdown
? Available in an SOIC-16 Package

簡介

MP4657B屬于集成電路（IC）的LED驅(qū)動(dòng)器。由制造生產(chǎn)的MP4657BLED 驅(qū)動(dòng)器器件屬于 LED 驅(qū)動(dòng)器電源管理集成電路 (PMIC) 系列，可通過標(biāo)稱固定電壓的電源為負(fù)載（通常為發(fā)光二極管）提供電流，并且電流可控。它與用于電壓調(diào)節(jié)的類似產(chǎn)品的主要區(qū)別在于，這類器件提供較低的反饋電壓（以提高系統(tǒng)能效），而且通常可對器件工作點(diǎn)進(jìn)行外部控制，可在照明應(yīng)用中用于實(shí)現(xiàn)調(diào)光功能。