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Polarity Converter Disclosure Number: IPCOM000078393D
Original Publication Date: 1972-Dec-01
Included in the Prior Art Database: 2005-Feb-25
Document File: 2 page(s) / 40K

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Carroll, LB: AUTHOR


Circuit 10 provides a negative bias from a positive source.

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Polarity Converter

Circuit 10 provides a negative bias from a positive source.

Basically, circuit 10 includes series connected power multivibrator 11 and voltage doubler 12. Voltage regulator 13 is connected to the output of doubler
12. Multivibrator 11 is driven by clock 14. Alternatively, multivibrator 11 may be free-running.

In operation, positive voltage +V from a power supply such as a battery or the like, not shown, is applied to terminal 15. Transistor T1 and transistor T2 act in a complementary manner. Likewise, transistors T3 and T4 act in a complementary manner via their respective gating transistors T5 and T6. In addition, transistor T4 is turned on simultaneously when transistor T1 is in the ON condition. Likewise, transistor T3 is in an ON condition when transistor T2 is in an ON condition.

Assuming that transistor T2 is turned on, capacitor C1 charges to the voltage +V through diode D1 with the polarity indicated. When transistors T2 and T3 turn off, transistors T1 and T4 turn on. Transistor T4 places ground at node A. As a result, a negative voltage -V appears at the anode of diode D1. During this interval, capacitor C2 charges through transistor T1 and diode D2 to the negative voltage -V1 which appears at the anode of diode D1. On the next cycle, transistors T1 and T4 turn off and transistors T2 and T3 are turned on, causing the positive indicated electrode of capacitor C2 to be grounded via node B through transistor T3. At this time, capacitor C2...