L8532

DESCRIPTION

The UTC L8532 is a switch mode power supply controller

intended for low to medium power single stage power factor (PF)

corrected LED Drivers. The device is designed to operate in

critical conduction mode (CrM) and is suitable for flyback as well

as buck topologies. Constant on time CrM operation is particularly

suited for isolated flyback LED applications as the control scheme

is straightforward and very high efficiency can be achieved even

at low power levels. These are important in LED lighting to

comply with regulatory requirements and meet overall system

luminous efficacy requirements. In CrM, the switching frequency

will vary with line and load and switching losses are low as

recovery losses in the output rectifier are negligible since the

current goes to zero prior to reactivating the main MOSFET

switch.

The device features a programmable on time limiter, zero

current detect sense block, gate driver, trans-conductance error

amplifier as well as all PWM control circuitry and protection

functions required to implement a CrM switch mode power

supply. Moreover, for high efficiency, the device features low

startup current enabling fast, low loss charging of the V CC

capacitor. The current sense protection threshold has been set at

500 mV to minimize power dissipation in the external sense

resistor. To support the environmental operation range of Solid

State Lighting, the device is specified across a wide junction

temperature range of -40°C ~125°C.

FEATURES

* Very Low 24μA Typical Startup Current

* Constant On Time PWM Control

* Cycle-by-Cycle Current Protection

* Low Current Sense Threshold of 500mV

* Low 2mA Typical Operating Current

* Source 500mA/Sink 800mA Totem Pole Gate Driver

* Reference Design for TRIAC and Trailing Edge Line Dimmers

* Wide Operating Temperature Range

* No Input Voltage Sensing Requirement

* Enable Function and Overvoltage Protection

规格书L8532