# US 5,708,577 A · Regulated power supply > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,708,577 A - Document ID: US5708577A - Status: Granted - Kind: A - Application number: 08/662,363 - Filed: 1996-06-12 - Granted: 1998-01-13 - Earliest claimed: 1996-06-12 - Assignees: Audio Control - Inventors: Meredith Robert Mckinley - Web page: https://patentgrep.com/patent/US5708577A ## CPC - G05F 1/66: Regulating electric power - G05F: SYSTEMS FOR REGULATING ELECTRIC OR MAGNETIC VARIABLES ## Abstract A regulated power supply includes a transformer having a primary winding coupled to an AC power line, and a secondary winding coupled to a rectifier. A storage capacitor is coupled through a switching transistor to the rectifier, where the storage capacitor provides a DC output power terminal. A control circuit having a comparator amplifier is coupled to the secondary winding and to the switching transistor, and compares the voltage from the secondary winding to a reference voltage value. The switching transistor is turned on from 0 to positive voltage values, as output by the rectifier, to regulate the voltage applied to the capacitor. The switching transistor switches off when the input voltage value equals or exceeds the reference value. Several passive circuit elements (e.g., diodes, resistor-capacitor networks, etc.) slow the turn on and turn off time of the switching transistor to help eliminate switching noises and other EMI. ## Claims ### Claim 1 A regulated power supply for use with a supply of AC power comprising: first and second input terminals coupled to the supply of AC power and providing an AC power signal having an input frequency having a rising portion and a falling portion during each cycle; a transformer having a primary winding coupled to the first and second input terminals and a secondary winding that outputs the AC power signal; an input rectifier coupled to the secondary winding and rectifying the AC power signal output from the secondary winding so as to produce a rectified power signal; a switch element coupled to an output of the rectifier to receive the rectified power signal and provide a switched power signal, the switch element being conductive during at least a portion of the rising portion of each cycle of the AC power signal; a power storage device coupled to an output of the switch element to store the switched power signal and provide a stored power signal at an output terminal; and a control circuit coupled to the switch element and coupled to the secondary winding to monitor the AC power signal, the control circuit being adapted to cause the switch element to be non-conductive prior to an end of the falling portion of each cycle of the AC power signal and at a rate not greater than twice the input frequency. ### Claim 2 (depends on 1) The regulated power supply of claim 1, further comprising a voltage divider network coupled between the input rectifier and the control circuit, and wherein the control circuit compares a reference voltage value to a voltage value from the voltage divider network to cause the switch element to be non-conductive when the voltage value from the voltage divider network is equal to or greater than the reference voltage value. ### Claim 3 (depends on 1) The regulated power supply of claim 1 wherein the control circuit is coupled to the power storage device and monitors a voltage on the power storage device to cause the switch element to be non-conductive at first and second times when the voltage on the power storage device is equal to first and second voltage values, the first time being greater than the second time and the second voltage value being greater than the first voltage value. ### Claim 4 (depends on 1) The regulated power supply of claim 1 wherein the control circuit is coupled to the secondary winding of the transformer through the input rectifier. ### Claim 5 (depends on 1) The regulated power supply of claim 1, further comprising a diode coupled between the input rectifier and the control circuit, the diode slowing a time at which the switch element becomes conducting during each cycle of the AC power signal. ### Claim 6 (depends on 1) The regulated power supply of claim 1, further comprising a capacitor and a resistor coupled between the switch element and the control circuit, the capacitor and resistor slowing a time when the switch element becomes non-conducting during each cycle of the AC power signal. ### Claim 7 (depends on 1) The regulated power supply of claim 1 wherein the input frequency is approximately 60 Hz, the input rectifier is a full wave rectifier, the switch element is a transistor, the power storage device is a capacitor, and the control circuit is an operational amplifier. ### Claim 8 (depends on 1) The regulated power supply of claim 1 wherein the input rectifier, switch element and control circuit are monolithically integrated. ### Claim 9 A regulated power supply for use with a supply of AC power comprising: first and second input terminals coupled to the supply of AC power and providing an AC power signal having an input frequency, the AC power signal having a rising portion and a falling portion during each cycle; transformer having a primary winding coupled to the first and second input terminals and a secondary winding; an input rectifier coupled to the secondary winding and rectifying the AC power signal so as to produce a rectified power signal; a first switch element coupled to an output of the rectifier to receive the rectified power signal and provide a switched power signal, the switch element being conductive during at least a portion of the rising portion of each cycle of the AC power signal; a first power storage device coupled to an output of the first switch element to store the switched power signal and provide a stored DC power signal at an output terminal; a first voltage divider network coupled between the input rectifier and the control circuit to produce a monitored voltage value; and a control circuit coupled to the voltage divider network and the first switch element, the control circuit comparing a reference voltage value to the monitored voltage value and causing the first switch element to be non-conductive when the monitored voltage value is equal to the reference voltage value, prior to an end of the falling portion of each cycle of the AC power signal, and at a rate not greater than twice the input frequency. ### Claim 10 (depends on 9) The regulated power supply of claim 9, further comprising a feedback resistor coupled between the control circuit and the first storage device, the feedback resistor modifying the reference voltage based on a voltage on the first power storage device. ### Claim 11 (depends on 9) The regulated power supply of claim 9, further comprising a diode coupled between the input rectifier and the control circuit, the diode slowing a time when the first switch element becomes conducting during each cycle of the AC power signal. ### Claim 12 (depends on 9) The regulated power supply of claim 9, further comprising a capacitor and a resistor coupled between the first switch element and the control circuit, the capacitor and resistor slowing a time when the first switch element becomes non-conducting during each cycle of the AC power signal. ### Claim 13 (depends on 9) The regulated power supply of claim 9 wherein the input frequency is approximately 60 Hz, the input rectifier is a full wave rectifier, the first switch element is a transistor, the first power storage device is a capacitor, and the control circuit includes at least one operational amplifier. ### Claim 14 (depends on 9) The regulated power supply of claim 9 wherein the input rectifier, first switch element and control circuit are monolithically integrated. ### Claim 15 (depends on 9) The regulated power supply of claim 9, further comprising a second voltage divider network having a variable resistor and coupled to the control circuit, the second voltage divider network providing a selectable reference voltage value as the reference voltage value, and wherein the control circuit compares the selectable reference voltage value to the monitored voltage value. ### Claim 16 (depends on 9) The regulated power supply of claim 9, further comprising a second switch element coupled to the output of the rectifier, a second storage device coupled to an output of the second switch element, the first and second power storage devices providing positive and negative stored DC power signals, respectively, at output terminals. ### Claim 17 (depends on 9) The regulated power supply of claim 9, further comprising a resistor and a capacitor actually a resistor a serially coupled resistor and capacitor, a resistor and capacitor being coupled as a unit in parallel with the first switch element. ### Claim 18 (depends on 9) The regulated power supply of claim 9, further comprising at least one filtered capacitor coupled in parallel to the primary winding of the transformer. ### Claim 19 A method of providing a regulated output power signal based on a supply of AC power, comprising the steps of: receiving an AC power signal having an input frequency, and a rising and a falling portion during each cycle; transforming the AC power signal to provide a transformed AC power signal; rectifying the transformed AC power signal to provide a rectified power signal; intermittently passing the rectified power signal to provide a switched power signal, the switched power signal being provided during at least a portion of the rising portion of each cycle of the AC power signal; storing the switched power signal to provide a stored power signal as a regulated output power signal; monitoring the AC power signal; and based on the monitored AC power signal, causing the switched power signal to be provided prior to an end of the falling portion of each cycle of the AC power signal, and at a rate not greater than twice the input frequency. ### Claim 20 (depends on 19) The method of claim 19 wherein the step of providing the switched power signal includes the steps of: providing a reference voltage value; comparing a reference voltage value to a monitored voltage of the AC power signal; and providing the portions of the rising portion of each cycle of the AC power signal until the monitored voltage value equals the reference voltage value. ### Claim 21 (depends on 19) The method of claim 19 wherein the step of rectifying the AC power signal provides a full wave rectified power signal, and wherein the step of storing the switched power signal stores the switched power signal so as to provide a positive and a negative regulated output power signals.