# US 10,503,187 B1 · Apparatus for regulating a bias-voltage of a switching power supply > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,503,187 B1 - Document ID: US10503187B1 - Status: Granted - Kind: B1 - Application number: 16/178,426 - Filed: 2018-11-01 - Granted: 2019-12-10 - Earliest claimed: 2018-11-01 - Assignees: Silanna Asia Pte Ltd - Applicants: Silanna Asia Pte Ltd - Inventors: Stuart Ide Hodge, Jr. - Web page: https://patentgrep.com/patent/US10503187B1 ## CPC - G05F 1/575: characterised by the feedback circuit - G05F 1/461: {using an operational amplifier as final control device} - H02M 1/08: Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters - H02M 3/07: using capacitors charged and discharged alternately by semiconductor devices with control electrode {, e.g. charge pumps} - H02M 3/33507: {with automatic control of the output voltage or current, e.g. flyback converters (H02M3/33561, H02M3/33569 take precedence)} - G05F 1/618: using semiconductor devices in series and in parallel with the load as final control devices (G05F1/461 takes precedence) - H02M 1/0045: {Converters combining the concepts of switch-mode regulation and linear regulation, e.g. linear pre-regulator to switching converter, linear and switching converter in parallel, same converter or same transistor operating either in linear or switching mode} - G05F: SYSTEMS FOR REGULATING ELECTRIC OR MAGNETIC VARIABLES - 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 An apparatus for regulating a bias-voltage of a switching power supply is disclosed. The apparatus includes a cascode amplifier, feedback-circuit, and bias-regulator circuit. The cascode amplifier includes a common-gate transistor and common-source transistor, where a source of the common-gate transistor is in signal communication with a drain of the common-source transistor. The feedback-circuit is in signal communication with the source of the common-gate transistor and the drain of the common-source transistor and the bias-regulator circuit is in signal communication with a gate of the common-source transistor, a gate of the common-gate transistor, and the feedback-circuit. The feedback-circuit receives a drain-voltage from the drain of the common-source transistor and produces a feedback-voltage and the bias-regulator circuit is configured to receive the feedback-voltage and produce and regulate the bias-voltage. A gate-voltage is produced from the bias-voltage and the gate-voltage is injected into the gate of the common-gate transistor. ## Claims ### Claim 1 An apparatus for regulating a bias-voltage of a switching power supply, the apparatus comprising: a cascode amplifier having a common-gate transistor and a common-source transistor, wherein a source of the common-gate transistor is in signal communication with a drain of the common-source transistor; a feedback-circuit in signal communication with the source of the common-gate transistor and the drain of the common-source transistor, wherein the feedback-circuit is configured to receive a drain-voltage from the drain of the common-source transistor and produce a first feedback-voltage and a second feedback-voltage using the drain-voltage, the first feedback-voltage having a first voltage level and the second feedback-voltage having a second voltage level; and a bias-regulator circuit in signal communication with a gate of the common-source transistor, a gate of the common-gate transistor, and the feedback-circuit, wherein the bias-regulator circuit is configured to receive the first feedback-voltage and the second feedback-voltage and produce and regulate the bias-voltage using the first feedback-voltage and the second feedback-voltage, wherein a gate-voltage is produced from the bias-voltage, and wherein the gate-voltage is injected into the gate of the common-gate transistor. ### Claim 2 (depends on 1) The apparatus of claim 1, wherein the bias-regulator circuit includes a difference amplifier that compares the first feedback-voltage against a reference voltage to produce and regulate the bias-voltage, the difference amplifier being biased by the second feedback-voltage. ### Claim 3 (depends on 2) The apparatus of claim 2, wherein the difference amplifier includes an operational amplifier. ### Claim 4 (depends on 2) The apparatus of claim 2, wherein the gate of the common-source transistor is set to a drive signal. ### Claim 5 (depends on 1) The apparatus of claim 1, wherein the feedback-circuit includes a voltage-doubler circuit in signal communication with the source of the common-gate transistor and the drain of the common-source transistor, wherein the voltage-doubler circuit is configured to receive the drain-voltage from the drain of the common-source transistor and produce the second feedback-voltage, and wherein the second feedback-voltage is equal to approximately twice the drain-voltage. ### Claim 6 (depends on 5) The apparatus of claim 5, wherein the voltage-doubler circuit includes a charge pump doubling circuit. ### Claim 7 (depends on 1) The apparatus of claim 1, wherein the common-gate transistor is a junction field-effect transistor. ### Claim 8 (depends on 7) The apparatus of claim 7, wherein the common-source transistor is a metal-oxide-semiconductor field-effect transistor. ### Claim 9 (depends on 1) The apparatus of claim 1, further including a driver circuit in signal communication with the bias-regulator circuit and the gate of the common-gate transistor, wherein the gate-voltage is produced from the bias-voltage by the driver circuit. ### Claim 10 (depends on 9) The apparatus of claim 9, wherein the driver circuit includes a voltage-divider circuit, and wherein the voltage-divider circuit is configured to receive the bias-voltage and produce the gate-voltage. ### Claim 11 (depends on 10) The apparatus of claim 10, wherein the voltage-divider circuit includes a low-pass filter. ### Claim 12 (depends on 11) The apparatus of claim 11, wherein the gate-voltage is the bias-voltage. ### Claim 13 A method for regulating a bias-voltage of a switching power supply utilizing an apparatus having a cascode amplifier, feedback-circuit, and bias-regulator circuit, the method comprising: receiving a drain-voltage from a drain of a common-source transistor of the cascode amplifier; producing, by the feedback-circuit, a first feedback-voltage and a second feedback-voltage using the drain-voltage, the first feedback-voltage having a first voltage level and the second feedback-voltage having a second voltage level; producing the bias-voltage from the drain-voltage with the bias-regulator circuit using the first feedback-voltage and the second feedback-voltage; and injecting a gate-voltage at a gate of a common-gate transistor, wherein the gate-voltage is related to the bias-voltage, and wherein producing the bias-voltage includes regulating the bias-voltage. ### Claim 14 (depends on 13) The method of claim 13, wherein producing the bias-voltage from the first feedback-voltage and the second feedback-voltage includes comparing the first feedback-voltage against a reference voltage with a difference amplifier to produce and regulate the bias-voltage. ### Claim 15 (depends on 14) The method of claim 14, further including setting a gate of the common-source transistor to a drive signal. ### Claim 16 (depends on 13) The method of claim 13, wherein the second feedback-voltage is produced by a voltage-doubler circuit within the feedback-circuit, and wherein the second feedback-voltage is equal to approximately twice the drain-voltage. ### Claim 17 (depends on 16) The method of claim 16, wherein producing the bias-voltage from the first feedback-voltage includes comparing the first feedback-voltage against a reference voltage with a difference amplifier to produce and regulate the bias-voltage, the difference amplifier being biased by the second feedback-voltage, and further including setting a gate of the common-source transistor to a drive signal. ### Claim 18 (depends on 13) The method of claim 13, wherein injecting the gate-voltage at the gate of the common-gate transistor includes voltage dividing the bias-voltage to produce the gate-voltage with a voltage-divider circuit. ### Claim 19 (depends on 18) The method of claim 18, further including low-pass filtering the bias-voltage to produce the gate-voltage with the voltage-divider circuit. ### Claim 20 (depends on 13) The method of claim 13, wherein the gate-voltage is the bias-voltage.