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High Voltage Pulse Switching Circuit

IP.com Disclosure Number: IPCOM000096602D
Original Publication Date: 1963-Aug-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 57K

Publishing Venue

IBM

Related People

Martin, VC: AUTHOR

Abstract

In circuit A, two silicon controlled rectifiers (SCR's) 10 and 11 are connected in series with load resistor 12 to form a high voltage inverter. Bypass resistors 13 and 14 insure that SCR's 10 and 11 share the voltage in proportion to their breakdown voltages. Resistor 15 limits the gate current in SCR 11. Diode 16 limits the cathode voltage and gate voltage of SCR 11, when SCR 10 is turned off. The maximum voltage across SCR 10 is also thus limited. When SCR 10 is turned off by inverter transistor 17 being in its conductive state, SCR 10 interrupts the cathode current of SCR 11 so that it also turns off. Capacitor 18 acts to maintain the bypass voltage constant against turn-on and turnoff transients. Curves 19 and 20 show the voltage pattern where the relationship is R13/R14 approx. = VBo of SCR 10/VBo of SCR 11.

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High Voltage Pulse Switching Circuit

In circuit A, two silicon controlled rectifiers (SCR's) 10 and 11 are connected in series with load resistor 12 to form a high voltage inverter. Bypass resistors 13 and 14 insure that SCR's 10 and 11 share the voltage in proportion to their breakdown voltages. Resistor 15 limits the gate current in SCR 11. Diode 16 limits the cathode voltage and gate voltage of SCR 11, when SCR 10 is turned off. The maximum voltage across SCR 10 is also thus limited. When SCR 10 is turned off by inverter transistor 17 being in its conductive state, SCR 10 interrupts the cathode current of SCR 11 so that it also turns off. Capacitor 18 acts to maintain the bypass voltage constant against turn-on and turnoff transients. Curves 19 and 20 show the voltage pattern where the relationship is R13/R14 approx. = VBo of SCR 10/VBo of SCR 11. VBo is the breakover voltage.

In circuit B, the inverter of circuit A is connected through load resistors R23 and R24 to SCR's 21 and 22 connected in series as a cathode follower output. A divided input to the gates of SCR's 21 and 22 from load resistors 23 and 24 is provided by leads 25 and 26. By dividing the outputs from the R23 and R24, the gate to anode voltages of the SCR's 21 and 22 is limited to one-half-the total output swig permitting use of lower voltage devices. Diodes 28 and 29 are high forward drop diodes of approximately four volts to prevent excessive reverse gate to cathode voltage and provide a driv...