# US 9,438,101 B1 · High speed switching solid state relay circuit > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,438,101 B1 - Document ID: US9438101B1 - Status: Granted - Kind: B1 - Application number: 14/706,010 - Filed: 2015-05-07 - Granted: 2016-09-06 - Earliest claimed: 2015-05-07 - Assignees: QM Power, Inc. - Applicants: QM Power, Inc. - Inventors: Charles J. Flynn; Cooper Tracy; Scott Hunter - Web page: https://patentgrep.com/patent/US9438101B1 ## CPC - H03K 17/785: controlling field-effect transistor switches - H02J 4/00: Circuit arrangements for mains or distribution networks not specified as AC or DC; Circuit arrangements for mains or distribution networks combining AC and DC sections or sub-networks (arrangements using intermediate DC-AC-DC conversion H02J1/002; arrangements using high-voltage DC [HVDC] links H02J3/36) - H02M 1/32: Means for protecting converters other than automatic disconnection - H02M 7/2176: {comprising a passive stage to generate a rectified sinusoidal voltage and a controlled switching element in series between such stage and the output} - H03K 17/6871: {the output circuit comprising more than one controlled field-effect transistor} - H02M 5/2937: {using whole cycle control, i.e. switching an integer number of whole or half cycles of the AC input voltage} - H03K: PULSE TECHNIQUE (measuring pulse characteristics G01R; modulating sinusoidal oscillations with pulses H03C; transmission of digital information H04L; discriminator circuits detecting phase difference between two signals by counting or integrating cycles of oscillation H03D3/04; automatic control, starting, synchronisation or stabilisation of generators of electronic oscillations or pulses where the type of generator is irrelevant or unspecified H03L; coding, decoding or code conversion, in general H03M) - H02J: ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY - H02M: APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF (transformers H01F; dynamo-electric converters H02K47/00; controlling transformers, reactors or choke coils, control or regulation of electric motors, generators or dynamo-electric converters H02P) ## Abstract The invention discloses a high speed switching solid state relay circuit with a switching section, a current limiting section and a voltage limiting section. The switching section comprises a bridge rectifier receiving the load voltage inputs, a MOSFET with a source connected to the negative voltage of the load through the bridge rectifier, a drain connected to the load voltage output, and a gate. The switching section further includes an isolator circuit comprising an optically-coupled LED. The isolator circuit is configured to receive a logic input signal and generate an isolated output signal based on the logic input signal, and the gate of the MOSFET is driven by the isolated output signal. The current limiting section includes a first set of resistors connecting the voltage drop across the load to the gate of the MOSFET through diodes. The voltage limiting section comprises a Zener diode connected to the gate of the MOSFET. ## Claims ### Claim 1 An electronic circuit for high speed switching from a power source to a load, comprising: a switching section comprising a bridge rectifier receiving the load voltage inputs; a MOSFET with a source connected to a negative voltage of the load through the bridge rectifier, a drain connected to the load voltage output, and a gate; and an isolator circuit comprising an optically-coupled LED, wherein the isolator circuit is configured to receive a logic input signal and generate an isolated output signal based on the logic input signal; and wherein the gate of the MOSFET is driven by the isolated output signal; and a current limiting section, comprising a first set of resistors connecting the voltage drop across the load to the gate of the MOSFET through diodes; wherein the first set of resistors and the diodes are configured to limit current flowing to the gate of the MOSFET; and a voltage limiting section, comprising a Zener diode connected to the gate of the MOSFET and configured to clamp the voltage to the gate below the maximum voltage rating of the MOSFET. ### Claim 2 (depends on 1) The circuit of claim 1, wherein the current limiting section further comprises a control circuit with a control transistor and a second set of resistors; wherein the control transistor electrically connects the gate of MOSFET to the source of the MOSFET when the control transistor is ON thereby turning OFF the MOSFET, and wherein the control transistor is turned OFF when the isolator circuit output signal is turned ON. ### Claim 3 (depends on 2) The circuit of claim 2, wherein the control circuit further comprises a first capacitor configured to filter noise from the diodes and a second capacitor configured to maintain the gate of the MOSFET at a positive voltage. ### Claim 4 (depends on 1) The circuit of claim 1, wherein the bridge rectifier is configured to maintain the MOSFET source at a negative voltage and the MOSFET drain at a positive voltage. ### Claim 5 (depends on 1) The circuit of claim 1, wherein the diodes are identical and are configured to allow only positive voltage to the gate of MOSFET with reference to the MOSFET source. ### Claim 6 (depends on 2) The circuit of claim 2, wherein the second set of resistors are low value resistors. ### Claim 7 (depends on 6) The circuit of claim 6, wherein one low value resistor is configured to constraint the instantaneous current drawn when the MOSFET Q1 is turned ON and the other low value resistor is configured to limit current to the Zener diode. ### Claim 8 (depends on 6) The circuit of claim 6, wherein the first set of resistors are high value resistors. ### Claim 9 (depends on 6) The circuit of claim 6, further comprising a high value pull-up resistor connected between the diodes and the base of the control transistor. ### Claim 10 (depends on 1) The circuit of claim 1, wherein the load is an AC load. ### Claim 11 (depends on 1) The circuit of claim 1, wherein the load is a DC load.