Browse Prior Art Database

Push Push Power Inverter

IP.com Disclosure Number: IPCOM000085511D
Original Publication Date: 1976-Apr-01
Included in the Prior Art Database: 2005-Mar-02
Document File: 2 page(s) / 32K

Publishing Venue

IBM

Related People

Beesley, JP: AUTHOR

Abstract

Transistor switching regulators frequently require a transformer stage to reduce the input voltage from rectified line voltage (typically 300V) to working load voltage (typically 5V).

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Push Push Power Inverter

Transistor switching regulators frequently require a transformer stage to reduce the input voltage from rectified line voltage (typically 300V) to working load voltage (typically 5V).

In the illustrated regulator, the primary regulating function is provided by on- off operation of transistor 10 under the control of pulse width modulation circuit
12. The output current of transistor 10 is fed to filter inductor L and thence in parallel to primaries 14, 16 of step-down transformers 18, 20 under the separate control of transistor or other suitable switches S1 and S2.

Switches S1 and S2 operate out-of-phase and for at least 180 degrees each, so that the current drawn through inductor L is substantially continuous. Free- wheeling diode FWD is provided to conduct this current during the off-times of transistor 10. Thus, the usual preregulator filter capacitor is omitted entirely. Capacitor C1 provides filtering and low impedance output at the load terminals. E clamp not only resets transformers 18 and 20, but also absorbs any surges during the operation of switches S1 and S2.

The secondaries 22, 24 are shown diode-ORed to a single load. Alternatively, they could supply separate loads.

Since primaries 14 and 16 are in separate transformers 18, 20, the problem of "walking the core" seen in push-pull inverters is avoided. Since switches S1 and S2 overlap in operation, stresses in these switches are minimized.

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