Active Shunt Regulator and Pre-Load
For multi-output power supplies, an active shunt regulator and pre-load circuit may be used to prevent rising output voltages under unbalanced loading conditions.
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Circuit Designs present tips and tricks for solving problems of interest to power supply designers. Here is where PI Applications Engineers turn their training and experience into practical circuit designs that can be employed to quickly and straightforwardly address problems of the sort that working designers often encounter.
Note: These ideas are presented for informational purposes only and Power Integrations makes no warranty herein expressed or implied.
Buffered Line Sense Resistors
A scaling buffer circuit for sensing a high DC input voltage is shown. The circuit can be used with a power converter controller.
Core Coupled Foil and Capacitance for Reduction of Common Mode Current
Reduction of common-mode current in the input lines may be achieved by attaching copper foil between the core of the transformer and the switching node of a power switch. Further reduction can also be achieved by connecting a capacitor between an input-referenced bias winding and a copper foil attached to
Design of 5V, 2A Charger in a 1-Inch-Cube Using InnoSwitch-CH (INN2024K)
This Engineering Test Report describes the design of a 5V, 2A USB charger that fits into a 1-inch square cube form factor. It uses InnoSwitch-CH (INN2024K).
Designing a Forward Converter Using TOPSwitch-GX
A sensing circuit enables design of a forward converter using TOPSwitch-GX by ensuring that the transformer resets each cycle.
Ferrite Magamp on Flyback PS
For a dual output flyback power supply, a ferrite magamp is used to regulate within tolerances levels when one output goes to no-load.
Floating Constant Current Source to Enable Start-up
Externally fed current into the BYPASS (BP) pin from a floating constant current source enables start-up of the controller for a wide range of input voltages.
High-bandwidth PFC Control Technique Single Stage ACDC Converter
An alternative power factor correction (PFC) control technique is introduced to design high-bandwidth PFC controller for the off-line single-stage power converters. It may be used in commercial or consumer products including LED driver and appliances.
Improved PFC Feedback Loop
An improved feedback loop process is introduced for power factor correction (PFC) controllers in single-stage AC-DC power converters. It reduces external component count and simplifies end-user tuning for the external components of error compensation.
Inductive Charging Circuit for Operational Power
Inductive charging circuit provides average bias current to the BP terminal and operational power for a power converter controller.
Input Bridge Rectifier with Fast Recovery Diodes for Reduced EMI
This circuit simplifies and reduces the cost of the electromagnetic interference (EMI) filter circuitry for AC-DC converters by using fast recovery diodes in the input bridge rectifier.
Input Line Regulation Circuit for HS Switching Buck Converter
An efficient simple circuit with low component count may be added to the feedback circuitry of a high-side switching buck converter to dramatically improve the input line regulation.
Overpower Overcurrent Protection Using Crowbar Circuit
The circuit provides overpower protection (OPP) or overcurrent protection (OCP) by using an active pre-load circuit to trigger an existing crowbar circuit used for overvoltage protection (OVP).
Phase Controlled Active Filter for an LED Driver
LED driver with a controlled active filter which is activated by a secondary-side phase detection circuit to enable the controlled active filter during low conduction angles of a dimmer circuit, such as a TRIAC dimmer. The controlled active filter can reduce shimmer and flicker of an LED load due to
Power Factor Enhancer from Full to Light Load Conditions
Power Factor Enhancer (PFE) may be used in a power factor correction (PFC) controller to increase the power factor (PF) of a power converter. The PFE may provide controlled distortion of the sensed current of the power converter to improve PF. At high line input voltages, where power factor correction
Power Supply Output Disable Circuit with Reduced Current Spikes
A power supply output disable circuit includes a series pass switch with additional capacitance to reduce turn-on current spikes of the series pass switch.
Primary-Side Control for CCM Flyback PS
A primary-side controller for an isolated flyback power supply operating in continuous conduction mode (CCM) may use a primary-side winding to sense and to regulate the output voltage.
Primary-Side Control for DCM Flyback PS
A primary-side controller for an isolated flyback power supply operating in discontinuous conduction mode (DCM) may use a primary-side winding to sense and to regulate the output voltage.
Programmable Synchronous Rectifier for Zero Voltage Switching
The synchronous output rectifier of a power converter may be used to facilitate Zero Voltage Switching (ZVS) of the main power switch of the power converter to reduce switching losses.
Stacked Transistor in a High-Side Buck to Increase Input Voltage Range
This Circuit Idea presents an implementation of stacking an external transistor, such as a MOSFET, in series with a high side switch of a buck regulator. The stacked MOSFET could expand the operational input voltage range of the PI LinkSwitch-TN2Q integrated buck controller beyond the typical operating input range for
Synchronous Rectifier Spike Reduction During Continuous Conduction Mode Operation of a Power Converter
An active switch QAUX is used to reduce the voltage spike on a synchronous rectifier (SR) QSR which may occur during continuous conduction mode (CCM) operation of a power converter. The use of the active switch QAUX also provides zero voltage switching (ZVS) for the turn-on of
V Pin Protection Circuit
A controller may use an internal clamp circuit that conducts current from the V pin to prevent damage to the internal ESD (electrostatic discharge) protection structure.
