Summary:

CX7509CX is a current mode PWM control chip with built-in high-voltage power MOSFET, suitable for solutions with power above 18W.

CX7509CX operates at a fixed switching frequency in PWM mode, which is precisely set internally. When unloaded or lightly loaded, the operating frequency is adjusted internally by the IC. The chip can work in green mode to reduce losses during light loads and improve the overall work efficiency. During startup and operation, only a small current is required, and a large resistor can be used in the startup circuit to further reduce power consumption during standby.

CX7509CX chip has a built-in slope compensation circuit, which avoids the occurrence of subharmonic oscillations and improves system stability when the circuit operates at a high duty cycle. The built-in leading edge blanking time eliminates the impact of diode reverse recovery current in the buffer network on the circuit.

CX7509CX adopts jitter technology, which can effectively improve the EMI performance of the system. The frequency hopping frequency of the system is set above the audio frequency (22KHz), which can avoid system noise during operation. Various protections are built-in, including cycle by cycle current limiting protection (OCP), overvoltage protection (VDD OVP), VDD overvoltage clamping, undervoltage protection (UVLO), over temperature protection (OTP), etc. The EMI characteristics of the system can be better improved through the internal soft drive structure.

Characteristic:

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

• Built in soft start to reduce stress on Vds on MOSFETs

• Frequency jitter function to improve EMI performance

• Frequency hopping mode improves light load efficiency and reduces standby power consumption

• Fixed 65KHz switching frequency

• Built in synchronous slope compensation

• Low starting current, low working current

• Built in Leading Edge Blanking (LEB) function

• Constant power output

• Cycle by cycle current limiting protection (OCP)

• VDD overvoltage protection, undervoltage protection (UVLO), VDD voltage clamping

• Secondary output diode short circuit protection

• Over temperature protection (OTP)

• Package SOP-8L

Application:

• Charger

• Suitable for PDA, digital camera, camera power adapter

• Set-top box power supply

• Open frame switching power supply

• Personal computer auxiliary power supply