Multi-Mode PFC and Current Mode LLC Controller With Programmable Audible Noise Reduction Control

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Product Information

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The HR1211 is a multi-mode PFC and current mode LLC combo controller that is configurable via UART interface. Power-saving technology helps achieve optimized efficiency across the full operating range.

The PFC controller employs a patented, digital average current control scheme to achieve hybrid CCM/DCM operation. Under heavy loads, CCM reduces the peak MOSFET current so the controller can be used across a wider load range. Under light loads, DCM reduces the switching frequency for better efficiency. Burst mode has configurable, digital soft switching to improve both light-load efficiency and audible noise.

Current mode control is implemented in the LLC stage to achieve good stability and fast response. Three operation modes are implemented based on the different load conditions: steady state, skip, and burst mode. This allows different load conditions to be independently optimized for efficiency. At light loads, digital, frequency-controlled burst mode is applied to reduce both switching power loss and audible noise. Adaptive dead-time adjustment (ADTA) and capacitive mode protection (CMP) is also applied to guarantee zero-voltage switching (ZVS) without capacitive mode operation.

The HR1211 has an internal, high-voltage current source for start-up, meaning that a traditional start-up resistor or external circuit is not required. The high-voltage (HV) current source can be implemented as an X-capacitor discharger when the AC input is in dropout, so a capacitor resistor is not required.

Protections include thermal shutdown (TSD), PFC open-loop protection (OLP), over-voltage protection (OVP), over-current limit (OCL) and LLC over-current protection (OCP), SO pin protection, and over-power protection (OPP).

The HR1211 is available in SOIC-20 and TSSOP-20 packages.

Advantages Include:

  • CCM/DCM multi-mode PFC control with high efficiency (light-load efficiency ? > 80%)
  • <100mW no-load power loss
  • High power factor due to capacitor current compensation (>0.95 at 20% loads)
  • UART interface and GUI to configure parameters


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