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High Voltage Supply Self Resonant Transformer

IP.com Disclosure Number: IPCOM000080996D
Original Publication Date: 1974-Mar-01
Included in the Prior Art Database: 2005-Feb-27
Document File: 2 page(s) / 48K

Publishing Venue

IBM

Related People

Phillips, DW: AUTHOR [+3]

Abstract

This power supply provides high voltage to the deflection plates in an ink jet printer, while occupying only a relatively small volume. Typically the size of the supply is in the range of 1.04 cubic inches. The supply uses an input voltage of 24 volts DC and has an output voltage that can reach as high as 2.8 kilovolts DC.

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High Voltage Supply Self Resonant Transformer

This power supply provides high voltage to the deflection plates in an ink jet printer, while occupying only a relatively small volume. Typically the size of the supply is in the range of 1.04 cubic inches. The supply uses an input voltage of 24 volts DC and has an output voltage that can reach as high as 2.8 kilovolts DC.

In Fig. 1, voltage regulator 1 regulates the 24 volt input down to the voltage necessary to produce the desired output. Inductor 2 provides a relatively constant current to the self-resonant transformer stage 3, which converts the DC voltage to AC and steps the voltage up to one-half of the desired output. Rectifier circuit 4 doubles the output voltage of transformer stage 3, and converts the sinusoidal output of the transformer to a DC voltage with very little ripple. The maximum voltage at the output is fixed by the turns ratio used on the transformer.

Fig. 2 shows a detailed circuit using this approach. The desired maximum output at terminal 6 is 2 kilovolts, hence there are 900 turns on the secondary and 17 turns on each half of the primary, giving a turns ratio of just under 53:1. There are at most 17 volts available from the 723 block to drop across each half of the primary of the transformer, which means that the turns ratio should be just under 59:1. Since this is a self-resonant transformer, a peak-to-peak voltage of
18.9 volts is dropped across the primary of the transformer, giving an out...