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US 4,675,798 AGranted
Direct coupled switching power supply with GTO SCR switching element
AssigneeHarris Corporation
InventorsSteve R. Jost, John S. Prentice
Life of this patent
Estimating the term…
Abstract
An improved switching arrangement for a direct coupled switching power supply is provided by utilizing a gate turn off SCR as the primary switching element and a second SCR as the turn-off control such that upon detection of any of a fully charged storage element, an excessive current through the gate turn off SCR, or an insufficient input voltage, the switch is turned off.
Claims17
An improved switching circuit for a direct coupled power converter comprising:
- a gate turn off SCR having and anode and an anode gate connected to a first AC input and having a cathode connected to a charge storage means and having a cathode gate connected via a bleeder resistor to said first AC input,
- a second SCR having an anode connected to said cathode gate of said gate turn off SCR, and having an anode gate connected via an anode gate bias resistor to said cathode gate of said gate turn off SCR, and having a cathode connected to a second AC input and having a a cathode gate,
- first means for providing a charging current level indicating signal in response to the current flowing from said cathode of said gate turn off SCR, said charging current level indicating signal being provided to said cathode gate of said second SCR,
- second means for providing a fully charged indicating signal in response to the voltage level on said cathode of said gate turn off SCR.
1 more element
An integrated switching power supply adapted for connection to an AC line without intervening voltage reducing means and adapted for connection to a charge storage means, comprising:
- first means for providing a current path from said AC line to said charge storage means when said AC line has a voltage exceeding the voltage on said charge storage means, said first means comprising a gate turn off SCR;
- second means for interrupting said current path when the voltage of said charge storage means exceeds a predetermined maximum voltage, said second means comprising a second SCR having its anode connected to the cathode gate of said gate turn off SCR;
- third means for interrupting said current path when the current through said current path exceeds a predetermined maximum current, and a zener diode having its cathode connected to the cathode of a second diode and its anode connected to a node, said second diode having its anode connected to the anode gate of said second SCR.
An improved integrated voltage pre-regulator adapted for direct connection to an AC line without external voltage reducing means comprising:
- (a) a switching means for ON-OFF switching of the flow of charging current through said pre-regulator when said AC line has a voltage exceeding a first voltage, said switching means comprising a gate turn off SCR having a resistor connected between an anode of said gate turn off SCR and a cathode gate of said gate turn off SCR such that application of a positive voltage across the anode to cathode of said gate turn off SCR will result in a current flow through said resistor and into said cathode gate of said gate turn off SCR to turn on said gate turn off SCR;
- (b) a control means for turning said switching means off to discontinue the flow of charging current through said switching means when said first voltage exceeds a predetermined maximum voltage, said control means also turning said switching means off to disconinue the flow of charging current through said switching means when said charging current exceeds a predetermined maximum current, said control means comprising:
- (i) a second SCR having an anode connected to said cathode gate of said gate turn off SCR, having an anode gate connected via an anode gate bias resistor to said cathode gate of said gate turn off SCR, having a cathode connected to said AC low line and having a cathode gate connected via a cathode gate bias resistor to said AC low line;
- (ii) a reference terminal for external connection to a source of reference voltage, said reference terminal connected to an anode of a zener diode having its cathode connected to a cathode of a diode, said diode having an anode connected to said anode gate of said second SCR, and
- (iii) a current sensing circuit for providing a bias voltage to said cathode gate bias resistor in response to a charging current flowing from said cathode of said gate turn off SCR such that said bias voltage exceeds one diode drop when said charging current exceeds a predetermined maximum current.
2 more elements
Dependencies are inferred from the claim text.