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Push-Pull Inverter

IP.com Disclosure Number: IPCOM000042768D
Original Publication Date: 1984-Jun-01
Included in the Prior Art Database: 2005-Feb-04
Document File: 2 page(s) / 45K

Publishing Venue

IBM

Related People

Chang, AY: AUTHOR [+3]

Abstract

The disclosed push-pull inverter logic circuit is characterized by parameter values which provide the same symmetrical signal swing around ground while providing a better speed-power product than a compensated current switch emitter follower. TIN1, TIN2, TIN3 and TIN4 of Fig. 1 are input devices. TSH is a level-adjusting device in order to use a -1.7-volt power supply. TUP and TDN provides a push-pull output. When either TIN1, TIN2, TIN3 or TIN4 is up, TSH and TDN are conducting. The current in TSH and TDN are determined by RE and RO, respectively. In that case, the output is VCC - IRC - VBE(TUP) (down-level). When all inputs are off, TSH and TDN are cut-off. Then the output is Since the output voltage is NĂ…375 mv, TDN will never be saturated. CE and CO are the speed boost capacitors.

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Push-Pull Inverter

The disclosed push-pull inverter logic circuit is characterized by parameter values which provide the same symmetrical signal swing around ground while providing a better speed-power product than a compensated current switch emitter follower. TIN1, TIN2, TIN3 and TIN4 of Fig. 1 are input devices. TSH is a level-adjusting device in order to use a -1.7-volt power supply. TUP and TDN provides a push-pull output. When either TIN1, TIN2, TIN3 or TIN4 is up, TSH and TDN are conducting. The current in TSH and TDN are determined by RE and RO, respectively. In that case, the output is VCC - IRC - VBE(TUP) (down- level). When all inputs are off, TSH and TDN are cut-off. Then the output is Since the output voltage is NÅ375 mv, TDN will never be saturated. CE and CO are the speed boost capacitors. Down level, and especially up level, noise tolerance is improved relative to the circuit of Fig. 1 in the circuit shown in Fig. 2. The circuit may be conveniently divided into two parts: (1) input and inverting switch, composed of TIN1-TIN4, TSH1, TSH2, RC and RE; and (2) push-pull output, composed of TUP, TDN and RO . The input section switches current between two paths, one path being through TSH1 and the other path through TSH2. RC, RE and VREF are designed to provide the proper control voltages at node A1 for driving the push-pull output. The push-pull output provides active pull-up by sourcing current through TUP, and active pull-down by sinking current thro...