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Voltage Converter

IP.com Disclosure Number: IPCOM000037756D
Original Publication Date: 1989-Jun-01
Included in the Prior Art Database: 2005-Jan-29
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Palmucci, CJ: AUTHOR

Abstract

In present high frequency power supply circuits, to drive two separate output voltages of polarity opposite to an input voltage requires two output drive devices. These devices drive into two separate, larger (to handle current capability) inductors into diode output filter network.

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Voltage Converter

In present high frequency power supply circuits, to drive two separate output voltages of polarity opposite to an input voltage requires two output drive devices. These devices drive into two separate, larger (to handle current capability) inductors into diode output filter network.

This invention eliminates output drive devices and larger inductors and parts count is much smaller, while achieving good voltage regulation at outputs.

Voltage is applied to divider R1, R2 and pin 7, module 1 (Fig. 1) and M2 output goes toward (+12v) supply voltage. Capacitor (C1) charges through time constant of R3 until pin 8 is higher than pin 7 and M1 output switches to low level. With M1 pin 1 a volt above ground, capacitor (C1) discharges current through (R3) resistor until (pin 8) input M1 is lower than in 7 and module M1 switches from low level to high level (toward +12v), thus setting the frequency of the converter circuit at 16 kht. Resistor (R4) keeps balance current flow in either direction from input to output, for M1, pin 7, and it forces M1 to switch faster.

With M1 operating as free-running multi-vibrator at high duty cycle, it is coupled to capacitor (C2,C3) to voltage doubles circuits. Voltage is received by diodes (D2,D3 and D4,D5) to "pi" filter LC network (L1,L2) and output filter capacitor's (C4,C5 and C6,C7). Thus, low ripple voltage is achieved at outputs at full load. Zener diode (D1) is used to sense voltage at M1, pin 7 and raise or lower...