# US 7,612,543 B2 · Current mode PWM boost circuit and feedback signal sensing method thereof > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,612,543 B2 - Document ID: US7612543B2 - Status: Granted - Kind: B2 - Application number: 11/670,038 - Filed: 2007-02-01 - Published: 2008-03-27 - Granted: 2009-11-03 - Earliest claimed: 2006-09-26 - Assignees: Advanced Analog Technology, Inc. - Inventors: Chien Peng Yu; Yi Cheng Wang; Ye Hsuan Yan - Web page: https://patentgrep.com/patent/US7612543B2 ## CPC - H02M 3/156: with automatic control of output voltage or current, e.g. switching regulators - H02M 1/08: Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters - 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 A feedback signal sensing method includes the steps of: providing a pulse width modulation (PWM) signal having a period; charging a capacitor by a current source during a pulse duration of the period, so as to form an equivalent slope compensation ramp signal; conducting an inductor current flowing from a boost inductor to flow through an equivalent resistor during the pulse duration of the period, so as to form an equivalent inductor current signal; and using a coupling characteristic of the capacitor together with the equivalent slope compensation ramp signal and the equivalent inductor current signal to form a feedback signal. ## Claims ### Claim 1 A feedback signal sensing method, applicable to a current mode pulse width modulation (PWM) boost circuit, said method comprising the steps of: providing a PWM signal having a period; charging a capacitor by a current source during a pulse duration of said period to form an equivalent slope compensation ramp signal; conducting an inductor current flowing from a boost inductor to flow through an equivalent resistor during said pulse duration to form an equivalent inductor current signal; and using a coupling characteristic of said capacitor together with said equivalent slope compensation ramp signal and said equivalent inductor current signal to form a feedback signal. ### Claim 2 (depends on 1) The feedback signal sensing method of claim 1, wherein the PWM signal is configured to turn on a switch inside the current mode PWM boost circuit in the pulse duration. ### Claim 3 (depends on 2) The feedback signal sensing method of claim 2, wherein the switch is a MOS transistor. ### Claim 4 (depends on 1) The feedback signal sensing method of claim 1, wherein the equivalent slope compensation ramp signal is defined by the following formula: IS×DTS/C wherein IS stands for a current of the current source, DTS stands for the pulse duration, and C stands for the capacitance of the capacitor. ### Claim 5 (depends on 1) The feedback signal sensing method of claim 1, wherein the equivalent slope compensation ramp signal is a voltage difference across two terminals of the capacitor. ### Claim 6 (depends on 1) The feedback signal sensing method of claim 1, wherein the equivalent resistor is a MOS transistor in a conductive state. ### Claim 7 (depends on 1) The feedback signal sensing method of claim 1, wherein the equivalent inductor current signal is a voltage signal, and is defined by the following formula: VIN×DTS×Rds/L wherein VIN stands for a voltage of a voltage source generating the inductor current, DTS stands for the pulse duration, Rds stands for the resistance of the equivalent resistor, and L stands for the inductance of the boost inductor. ### Claim 8 (depends on 1) The feedback signal sensing method of claim 1, wherein the feedback signal is the sum of the equivalent slope compensation ramp signal and the equivalent inductor current signal. ### Claim 9 (depends on 1) The feedback signal sensing method of claim 1, wherein the feedback signal is acquired at a connection point of the current source and the capacitor. ### Claim 10 A current mode PWM circuit comprising: a boost unit comprising a boost inductor and a switch, said boost unit being configured to increase voltage to generate a DC output voltage; a voltage dividing circuit configured for generating a divided voltage from said DC output voltage; an error amplifier configured to generate an error signal by comparing a reference voltage with said divided voltage; a comparator configured to generate a first signal by comparing said error signal with a feedback signal; a pulse width generator configured to receive said first signal and a second signal, said second signal coming from an oscillator to generate a third signal, wherein said third signal is configured to control said switch; said a feedback signal generating unit coupled to said boost unit to generate said feedback signal, wherein said feedback signal comprises an equivalent inductor current signal flowing through said boost inductor and an equivalent slope compensation ramp signal, said feedback signal generating unit comprising: a capacitor having a terminal coupled to a connection point of said boost inductor and said switch; and a current source coupled to another terminal of said capacitor. ### Claim 11 (depends on 10) The current mode PWM boost circuit of claim 10, wherein said boost unit further comprises: a rectifying diode connected to said connection point of said boost inductor and said switch; and an output capacitor connected between said rectifying diode and a ground terminal to generate said DC output voltage. ### Claim 12 (depends on 11) The current mode PWM boost circuit of claim 11, wherein said voltage dividing circuit comprises: a first resistor connected to said rectifying diode; and a second resistor connected between said rectifying diode and said ground terminal, wherein the divided voltage is acquired at a connection point of said first resistor and said second resistor. ### Claim 13 (depends on 10) The current mode PWM boost circuit of claim 10, further comprising a buffer connected to an output terminal of said pulse width generator to improve the driving capability of said third signal so as to control said switch. ### Claim 14 (depends on 10) The current mode PWM boost circuit of claim 10, wherein the equivalent slope compensation ramp signal is generated when the current source charges said capacitor with the switch turned on. ### Claim 15 (depends on 10) The current mode PWM boost circuit of claim 10, wherein the equivalent slope compensation ramp signal is associated with a current source, said capacitor, and a duty cycle of said pulse width generator. ### Claim 16 (depends on 10) The current mode PWM boost circuit of claim 10, wherein the equivalent inductor current signal is a voltage signal and is associated with a resistance of said switch when being turned on. ### Claim 17 (depends on 10) The current mode PWM boost circuit of claim 10, wherein the equivalent inductor current signal is a voltage signal and is associated with the voltage, said boost inductor, a resistance of said switch when being turned on, and a duty cycle of said pulse width generator.