Abstract:
A Power Factor Correction (PFC) controller includes an error amplifier for amplifying a difference between Vout and intended Vout to provide a power demand (Pdem) output at a compensation pin. A burst mode controller includes soft-start circuitry coupled to receive Pdem and to a drive pin which provides pulses to a control node of a power switch of a DC-DC converter during burst periods. The pulses slow ramping of line current over a first 2 to 36 switching cycles at a beginning of bursts when energizing the inductor to reduce a line current slope as compared to without ramping up, and for slowing ramping down of line current over the last 2 to 36 switching cycles to reduce a line current slope when de-energizing the inductor as compared to a line current without ramping down. The PFC controller does not utilize zero-crossings of the line voltage for burst period synchronization.
Abstract:
A method for operating a resonant converter in a burst mode includes determining the polarity of a transformer voltage across a secondary winding of a transformer. The method includes determining, from the polarity of the transformer voltage, on/off states of first and second transistors coupled to the secondary winding of the transformer. If the transformer voltage has a first polarity, the method includes commencing a burst period by alternately turning on/off high-side and low-side transistors electrically connected to a primary winding of the transformer.
Abstract:
A circuit includes a first driver, a second driver, and a burst mode control circuit coupled to the first and second drivers. The burst mode control circuit is configured to implement a burst mode operation having a burst soft-on portion and a burst portion. During the soft-on portion of the burst mode operation, the burst mode control circuit is configured to cause the first and second drivers to produce a first set of pulses of increasing pulse width. During the burst portion of the burst mode operation, the burst mode control circuit is configured to cause the first and second drivers to produce a second set of pulses of a constant pulse width.
Abstract:
A method for operating a resonant converter in a burst mode includes determining the polarity of a transformer voltage across a secondary winding of a transformer. The method includes determining, from the polarity of the transformer voltage, on/off states of first and second transistors coupled to the secondary winding of the transformer. If the transformer voltage has a first polarity, the method includes commencing a burst period by alternately turning on/off high-side and low-side transistors electrically connected to a primary winding of the transformer.
Abstract:
A switching converter controller includes: a control loop adapted to be coupled to an output terminal of a power stage; and a hybrid hysteretic control (HHC) circuit coupled to the control loop. The HHC circuit includes a resonant capacitor voltage (Vcr) node adapted to be coupled to a resonant capacitor (Cr) of the power stage, where the Vcr node sums a sense voltage for Cr with a frequency compensation ramp. The HHC circuit also includes a soft-start controller coupled to the Vcr node. The soft-start controller includes a clamp circuit coupled to the Vcr node.
Abstract:
A circuit includes a device monitoring component, a voltage error component, a current error component, a power error component, an error selecting component, a filter instruction component and a filter. The device monitoring component monitors load voltage and load current, and outputs a device state signal. The voltage error component outputs a voltage error signal. The current error component outputs a current error signal. The power error component outputs a power error signal. The error selecting component outputs a selected error signal. The filter instruction component outputs a filter instruction based on the device state signal. The filter outputs a modification signal to modify operation of a device so as to modify one of the load voltage, the load current and the load power.
Abstract:
A circuit includes a device monitoring component, a voltage error component, a current error component, a power error component, an error selecting component, a filter instruction component and a filter. The device monitoring component monitors load voltage and load current, and outputs a device state signal. The voltage error component outputs a voltage error signal. The current error component outputs a current error signal. The power error component outputs a power error signal. The error selecting component outputs a selected error signal. The filter instruction component outputs a filter instruction based on the device state signal. The filter outputs a modification signal to modify operation of a device so as to modify one of the load voltage, the load current and the load power.
Abstract:
Methods, control apparatus and series resonant or LLC power conversion systems are presented in which a resonant series circuit current is compared with a threshold during a portion of a modulation switching cycle following turn on of a corresponding switching device and one or more indications or remedial actions are undertaken to modify modulation control of a switching circuit in response to a determination that the resonant current is below the threshold to facilitate our promote zero voltage switching or near-zero voltage switching and provide current reversal protection.