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US 5,536,980 AGranted
High voltage, high current switching apparatus
AssigneeTexas Instruments Incorporated
InventorsKeith W. Kawate, John J. Chrupcala, Eric K. Larson, Thomas R. Maher
Life of this patent
Estimating the term…
Abstract
A high voltage, high current DC switch is shown having a single pole, double throw relay and a solid state power switch such as an IGBT or MOSFET transistor. Voltage is switched by means of the solid state switch while steady state current is conducted through the relay load contact. Several different protector devices are used in the event of circuit malfunction including a combination of thermal and current fuses and resettable thermostats.
Claims27
Relay apparatus for switching high voltage, high current DC circuits comprising:
- a first low voltage circuit having a low voltage power source, an on/off switch and a relay coil,
- a second high voltage circuit having a relay switch comprising a movable common contact connected to the high voltage negative side of the circuit, a first normally open contact and a second normally closed contact, a contact arm mounting the movable contact with the movable contact movable in response to energization of the relay coil between the first and second contacts,
- a high voltage power source and a load terminal connected to the first normally open contact,
- a solid state power switch having main terminals and a terminal to control the state of energization of the power switch,
- a first current path comprising resistor means connected to the second normally closed contact, the high voltage source and the terminal controlling the state energization of the power source switch, and a zener diode connected between the terminal controlling the state of energization of the power switch and the common contact,
- a second current path in which the main terminals of the power switch are connected between the first normally open contact and the common contact, energization of the relay coil causing the movable common contact to move out of engagement with the second normally closed contact to increase the voltage of the said terminal to control the state of energization of the power switch through the resistor means to energize the power switch after the movable common contact has moved out of engagement with the second normally closed contact and prior to the engagement of the movable common contact with the first normally open contact and maintain the power switch energized until the movable common contact moves back into engagement with the second normally closed contact following de-energization of the relay coil.
3 more elements
Relay apparatus for switching high voltage, high current DC circuits comprising:
- a first low voltage circuit having a low voltage power source, an on/off switch and a relay coil,
- a second high voltage circuit having a relay switch comprising a movable common contact, a first normally open contact and a second normally closed contact, a contact arm mounting the movable contact with the movable contact movable in response to energization of the relay coil from the second to the first contact and upon de-energization from the first contact to the second contact,
- a high voltage power source and a load terminal connected to the first normally open contact,
- a solid state power switch having main terminals and a terminal to control the state of energization of the power switch,
- a current path in which the main terminals of the power switch are connected between the first normally open contact and the common contact, and
- means for biasing the solid state switch on upon energization of the relay coil as soon as the movable contact moves away from the second contact turning on the solid state switch before the movable contact engages the first contact, essentially all the current from the high voltage source flowing through the first contact after the movable contact engages the first contact with the bias being maintained on the solid state switch, and upon de-energization of the relay coil with the solid state switch still biased on, current flow through the first contact being interrupted when the movable contact leaves the first contact and means for removing the bias from the solid state switch when the movable contact engages the second contact.
3 more elements
Apparatus for switching high voltage, high current DC circuits comprising:
- a high voltage circuit having a switch comprising a movable common contact, a first normally open contact and a second normally closed contact, a contact arm mounting the movable contact with the movable contact movable between the first and second contacts,
- a high voltage power source and a load terminal connected to the first normally open contact,
- a solid state power switch having main terminals and a terminal to control the state of energization of the power switch,
- a current path in which the main terminals of the power switch are connected between the first normally open contact and the common contact, and
- means for biasing the solid state switch on as soon as the movable contact moves away from the second contact turning on the solid state switch before the movable contact engages the first contact, essentially all the current from the high voltage source flowing through the first contact after the movable contact engages the first contact with the bias being maintained on the solid state switch keeping the solid state switch on, current flow through the first contact being interrupted when the movable contact leaves the first contact and means for removing the bias from the solid state switch to turn the switch off when the movable contact engages the second contact.
2 more elements
Dependencies are inferred from the claim text.