Overview

The CX7520 is a primary side power control IC that incorporates a high-voltage Super Junction N-Channel MOSFET and adopts current mode control. It is applied in SSR power supply solutions with power up to 25W.

In PWM mode, it operates at a fixed switching frequency, which is precisely set internally. Under no-load or light-load conditions, the operating frequency is adjusted by the internal IC.

The IC can operate in green mode to reduce light-load losses and improve overall system efficiency. It requires only a very small current during startup and operation, allowing the use of a large resistor in the startup circuit to further reduce standby power consumption. The chip features built-in slope compensation to prevent sub-harmonic oscillations and improve system stability when operating at a large duty cycle. A built-in leading-edge blanking time eliminates the influence of the diode reverse recovery current in the snubber network on the circuit.

The CX7520 employs frequency jittering technology, which effectively improves the system's EMI performance. The system's burst frequency is set above the audio frequency (22kHz), preventing audible noise during operation.

The CX7520 integrates multiple protections, including cycle-by-cycle current limiting (OCP), over-voltage protection (VDD OVP), VDD over-voltage clamping, under-voltage lockout (UVLO), over-temperature protection (OTP), etc. The internal soft-drive structure further improves the system's EMI characteristics.

Features

- Standby power consumption less than 75mW for full voltage range (90Vac-265Vac) input

- Built-in soft-start to reduce Vds stress on the MOSFET

- Frequency jittering function to improve EMI performance

- Burst mode operation to improve light-load efficiency and reduce standby power consumption

- Fixed 65KHz switching frequency

- Built-in synchronous slope compensation

- Low startup current, low operating current

- Built-in leading-edge blanking (LEB) function

- Built-in overload protection (OLP)

- Cycle-by-cycle current limiting (OCP)

- VDD over-voltage protection, under-voltage lockout (UVLO), VDD voltage clamping

- Secondary output diode short circuit protection

- Over-temperature protection (OTP)

- Available in SOP-8L package

Applications

- PD, QC and other fast charger adapters

- Power adapters for PDAs, digital cameras, camcorders

- Set-top box power supplies

- Open frame switching power supplies

- Personal computer auxiliary power supplies