onsemi FAN6604MRMX

The FAN6604MRMX is a highly integrated Green-Mode PWM controller produced by onsemi. This controller is designed to enhance the performance of flyback converters, particularly in general-purpose switch-mode power supplies (SMPS) and power adapters. It features a proprietary Green-Mode function that reduces standby power consumption by modulating the off-time and switching frequency under light-load and no-load conditions. The controller also includes various protection mechanisms such as AC input brownout protection, sense pin short-circuit protection, and over-temperature protection, ensuring reliable and efficient operation.

• Green-Mode Operation: Off-time modulation to reduce switching frequency under light-load and no-load conditions, entering 'deep' Burst Mode to save PWM pulses and meet international power conservation requirements.
• Frequency Hopping: Reduces EMI emission with minimum line filters.
• Peak-Current-Mode Control: Regulates output voltage and provides pulse-by-pulse current limiting.
• Leading-Edge Blanking (LEB): Prevents premature termination of the switching pulse due to turn-on spikes.
• Under-Voltage Lockout (UVLO): Ensures the IC operates within safe voltage thresholds (17 V start, 10 V minimum operating voltage).
• Gate Output Protection: Internally clamped at 13 V to protect the external MOSFET from over-voltage damage.
• Soft-Start Function: Reduces inrush current and output voltage overshoot during startup.
• Slope Compensation: Improves stability and prevents sub-harmonic oscillation.
• Brownout Protection: Detects AC line voltage and performs brownout protection using the HV pin.
• Over-Temperature Protection (OTP): Uses an external NTC thermistor to sense temperature and latch-off the controller if thresholds are exceeded.
• Sense Pin Short-Circuit Protection (SSCP): Protects against short-circuits on the sense pin.

The FAN6604MRMX is suitable for various applications, including:

• General-purpose switch-mode power supplies (SMPS): Enhances performance and efficiency in SMPS designs.
• Flyback power converters: Optimizes the operation of flyback converters with features like Green-Mode and frequency hopping.
• Power adapters: Used in power adapters to ensure high efficiency and compliance with international power conservation standards.

1. What is the primary function of the FAN6604MRMX?

   The FAN6604MRMX is a highly integrated Green-Mode PWM controller designed to enhance the performance of flyback converters and general-purpose switch-mode power supplies.

2. What is the Green-Mode function in the FAN6604MRMX?

   The Green-Mode function reduces standby power consumption by modulating the off-time and switching frequency under light-load and no-load conditions.

3. What is the fixed PWM frequency of the FAN6604MRMX?

   The fixed PWM frequency is typically 65 kHz.

4. How does the FAN6604MRMX protect against over-voltage?

   The FAN6604MRMX includes VDD over-voltage protection (OVP) and an internal latch circuit to latch-off the controller if OVP or over-temperature protection (OTP) thresholds are exceeded.

5. What is the purpose of the Leading-Edge Blanking (LEB) feature?

   The LEB feature prevents premature termination of the switching pulse due to turn-on spikes on the sense resistor.

6. How does the soft-start function work in the FAN6604MRMX?

   The built-in 8 ms soft-start function reduces the inrush current and output voltage overshoot during startup.

7. What is the maximum duty cycle of the FAN6604MRMX?

   The maximum duty cycle is 90%.

8. How does the FAN6604MRMX protect against brownout conditions?

   The FAN6604MRMX detects AC line voltage using the HV pin and performs brownout protection with hysteresis.

9. What is the operating temperature range of the FAN6604MRMX?

   The operating temperature range is -40°C to 105°C.

10. What package type is the FAN6604MRMX available in?

    The FAN6604MRMX is available in an 8-pin Small Outline Package (SOP).