Signal conversion circuits

Claim 2

In combination: two input terminals for receiving an alternating current input signal; a bidirectional switch; a load capacitor in series with the switch, the series circuit being connected between said input terminals; means including a phase shift circuit responsive to a first control signal manifestation for closing said bidirectional switch solely once each period of the alternating current input signal at a time to charge the capacitor in one sense and to a level dependent upon the amount of phase shift introduced by said phase shift circuit, said means being responsive to a second control signal manifestation for closing said bidirectional switch solely once each period of said alternating current input signal at a time to charge said capacitor in the opposite sense and to a level also dependent upon the phase shift introduced by said phase shift circuit thereby providing a direcT current output signal of either polarity and of controllable level across said capacitor.

Claim 3

The combination recited in claim 1 wherein said switch comprises a bidirectional triode thyristor having a conduction path and a gate terminal, said conduction path being connected in series with said load capacitor, said gate terminal for receiving a trigger signal.

Claim 4

The combination recited in claim 2 wherein said means including a phase shift circuit comprises: means for applying said alternating current signal to said phase shift circuit for producing a phase shifted alternating current output signal; two output terminals for receiving said phase shifted output signal; a circuit path connected between said two output terminals for conducting a path current there-between; threshold conduction means in series with said circuit path for enabling conduction of said path current when the potential across said threshold conduction means is greater than a threshold value of either polarity; further means in series with said circuit path, said further means being responsive to a third control signal manifestation for opening the path and being responsive to said first and second control signal manifestations for both closing the path and limiting the flow of current therethrough to a selected one of two directions; and means for deriving said trigger signal from said circuit path current and applying said trigger signal to said gate terminal of said bidirectional thyristor to charge said capacitor in a selected sense and to a selected level.

Claim 5

The combination recited in claim 3 wherein said further means comprises: means for connecting at least two parallel connected oppositely poled unilaterally conductive switches in series with said path for controlling the direction of flow of said path current in accordance with the conductive state of said switches.

Claim 6

The combination recited in claim 3 wherein said further means comprises: at least two parallel connected oppositely poled diodes, said parallel connected diodes being connected in series with said circuit path, and terminal means for connecting at least one separate switch in series with each of the parallel connected diodes thereby controlling the sense of said path current in accordance with the conductive state of said separate switches.

Claim 7

The combination recited in claim 3 wherein said means for deriving a trigger signal from said circuit path current comprises: a coupling transformer having two windings, one winding being connected in series with said circuit path, the other winding being connected between said gate terminal and one end of said conduction path of said thyristor.

Claim 8

The combination recited in claim 3 wherein said means for deriving a trigger signal from said circuit path comprises: a coupling capacitor connected between a point in said further means and said gate terminal of said thyristor; and a resistor connected between said point and one of said two output terminals.

Claim 9

The combination recited in claim 3 further comprising: a current limiting resistor connected in series with said conduction path of said thyristor for limiting the charging rate of said load capacitor when said thyristor is conductive.

Claim 10

A circuit for producing a direct voltage level of either polarity and of controllable magnitude from an alternating current input signal, comprising: two circuit input terminals for receiving said alternating current input signal; a bidirectional triode thyristor having first and second main terminals and a gate terminal, said second main terminal being connected to one of said circuit input terminals; a load capacitor for producing said direct voltage level of either polarity thereacross, said load capacitor being connected between said first main terminal and the other of said circuit input terminals; circuit means for controlling the magnitude of said direct voltage level of either polarity appEaring across said load capacitor, said circuit means being coupled across said input terminals and producing alternating polarity phase shifted trigger pulses in response to said alternating current input signal; and control means for controlling the polarity of said direct voltage level appearing across said load capacitor, said control means being receptive of said alternating polarity phase shifted trigger pulses and connected to said gate terminal, said control means being responsive to a first control signal for applying solely the positive ones of said trigger pulses to said gate terminal and responsive to a second control signal for applying solely the negative ones of said trigger pulses to said gate terminal.

Claim 11

A circuit for producing a direct voltage level of either polarity and of controllable magnitude from an alternating current input signal, comprising: two circuit input terminals for receiving said alternating current input signal; a bidirectional triode thyristor having first and second main terminals and a gate terminal, said second main terminal being connected to one of said circuit input terminals; a load capacitor for producing said direct voltage level of either polarity thereacross, said load capacitor being connected between said first main terminal and the other of said circuit input terminals; circuit means for controlling the magnitude of said direct voltage level of either polarity appEaring across said load capacitor, said circuit means being coupled across said input terminals and producing alternating polarity phase shifted trigger pulses in response to said alternating current input signal; and control means for controlling the polarity of said direct voltage level appearing across said load capacitor, said control means being receptive of said alternating polarity phase shifted trigger pulses and connected to said gate terminal, said control means being responsive to a first control signal for applying solely the positive ones of said trigger pulses to said gate terminal and responsive to a second control signal for applying solely the negative ones of said trigger pulses to said gate terminal.

Claim 12

The circuit recited in claim 9 further comprising a coupling capacitor connected to said gate terminal, a circuit point in said circuit means for providing said alternating polarity phase shifted trigger pulses and wherein said control means comprises first and second parallel connected oppositely poled unilaterally conductive switches, each being responsive to separate ones of said first and second control signals, said parallel connected switches being connected between said circuit point and said coupling capacitor.

Claim 13

The circuit recited in claim 10 wherein said first and second switches are transistor switches.

Claim 14

The circuit recited in claim 9 further comprising a current limiting resistor connected in series with said thyristor.

Claim 15

The circuit recited in claim 9 further comprising means for adjusting the phase of said trigger pulses relative to said alternating current input signal.