US5847554A
Expired / Lapsed
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Synchronous switching regulator which employs switch voltage-drop for current sensing
Assignee: Analog Devices International ULC
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Filing: 1997-06-13
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Granted: 1998-12-08
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Expires: 2017-06-13
Abstract
Abstract Synchronous switching regulator circuits with voltage-drop sensing circuitry are presented in which the current sensing element typically in series with a load is eliminated, resulting in reduced dissipative losses and less costly manufacture. Voltage drops are measured across the regulator's synchronous switching element, and, in some cases, also across the regulator's main switching element. Measured voltage drops are used to derive a current analog signal indicative of the amount of current being supplied by the regulator. The current signal is then compared with a threshold value to determine whether the regulator's duty cycle should be varied.
Inventors
- 👤 Milton E. Wilcox
- 👤 Christopher B. Umminger
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 12:13
CPC Classifications
H; H02; H02M; H02M3/00; H02M3/02; H02M3/04; H02M3/10; H02M3/145; H02M3/155; H02M3/156; H02M3/158; H02M3/1588; H02M1/00; H02M1/0003; H02M1/0009; Y; Y02; Y02B; Y02B70/00; Y02B70/10
Claims Analysis
Total Claims: 33
Claim 1
Independent Claim
131 words
A synchronous switching regulator circuit for supplying current at a regulated voltage to a load, said regulator circuit comprising: an input terminal for coupling to a source of input supply voltage; an output terminal for coupling to said load; control circuitry for regulating the duty cycle of said regulator circuit; output circuitry coupled to said input terminal, to said output terminal, and to said control circuitry, said output circuitry comprising an inductor, a main switching element that causes current in said inductor to increase, and a synchronous switching element that conducts said inductor current when said main switching element is non-conductive; and voltage-drop sensing circuitry coupled to said synchronous switching element and to said control circuitry for providing current information to said control circuitry when said synchronous switching element is conductive.
Claim 2
Dependent Claim
131 words
A synchronous switching regulator circuit for supplying current at a regulated voltage to a load, said regulator circuit comprising: an input terminal for coupling to a source of input supply voltage; an output terminal for coupling to said load; control circuitry for regulating the duty cycle of said regulator circuit; output circuitry coupled to said input terminal, to said output terminal, and to said control circuitry, said output circuitry comprising an inductor, a main switching element that causes current in said inductor to increase, and a synchronous switching element that conducts said inductor current when said main switching element is non-conductive; and voltage-drop sensing circuitry coupled to said synchronous switching element and to said control circuitry for providing current information to said control circuitry when said synchronous switching element is conductive.
Claim 3
Dependent Claim
33 words
The regulator circuit of claim 1 wherein said voltage-drop sensing circuitry comprises: a sense amplifier coupled to said output circuitry; and blanking circuitry coupled to said sense amplifier and to said control circuitry.
Claim 4
Dependent Claim
13 words
The regulator circuit of claim 1 wherein said regulator circuit operates in current-mode.
Claim 5
Dependent Claim
19 words
The regulator circuit of claim 3 wherein said voltage-drop sensing circuitry is also coupled to said main switching element.
Claim 6
Dependent Claim
56 words
The regulator circuit of claim 4 wherein said voltage-drop sensing circuitry comprises: first and second sense amplifiers coupled to said output circuitry; blanking circuitry coupled to said first and second sense amplifiers and to said control circuitry; and summation circuitry coupled to the outputs of said first and second sense amplifiers and to said control circuitry.
Claim 7
Dependent Claim
25 words
The regulator circuit of claim 5 wherein said voltage-drop sensing circuitry further comprises track-and-hold circuitry coupled to said summation circuitry and to said control circuitry.
Claim 8
Dependent Claim
38 words
The regulator circuit of claim 6 wherein said track-and-hold circuitry comprises: a switch coupled in series to said summation circuitry and to said control circuitry; and a capacitor coupled between said switch and said control circuitry to ground.
Claim 9
Dependent Claim
17 words
The regulator circuit of claim 5 wherein said first and second sense amplifiers each comprises track-and-hold circuitry.
Claim 10
Dependent Claim
16 words
The regulator circuit of claim 5 wherein said first and second sense amplifiers each provides gain.
Claim 11
Dependent Claim
46 words
The regulator circuit of claim 5 wherein said main and synchronous switching elements each comprise MOSFETs having mismatched R DS (ON) s, and at least one of said first and second sense amplifiers provides a gain that can compensate for said mismatched R DS (ON) s.
Claim 12
Dependent Claim
38 words
The regulator circuit of claim 3 wherein said control circuitry comprises: an oscillator; a latch coupled to said oscillator and to said output circuitry; and a current comparator coupled to said latch and to said voltage-drop sensing circuitry.
Claim 13
Dependent Claim
13 words
The regulator circuit of claim 1 wherein said regulator circuit operates in voltage-mode.
Claim 14
Dependent Claim
32 words
The regulator circuit of claim 12 wherein the maximum duty cycle of said regulator circuit is less than 100% to permit valid voltage-drop sensing of said synchronous switching element during each cycle.
Claim 15
Dependent Claim
37 words
The regulator circuit of claim 12 wherein said voltage-drop sensing circuitry comprises: a comparator coupled to said synchronous switching element and to said control circuitry; and blanking circuitry coupled to said control circuitry and to said comparator.
Claim 16
Dependent Claim
38 words
The regulator circuit of claim 12 wherein said control circuitry comprises: a pulse-width-modulator coupled to said voltage-drop sensing circuitry and to said output terminal; and a plurality of drivers coupled to said pulse-width-modulator and to said output circuitry.
Claim 17
Dependent Claim
14 words
The regulator circuit of claim 12 wherein said synchronous switching element comprises a MOSFET.
Claim 18
Dependent Claim
15 words
The regulator circuit of claim 12 wherein said synchronous switching element comprises a bipolar transistor.
Claim 19
Dependent Claim
15 words
The regulator circuit of claim 1 wherein said main and synchronous switching elements comprise MOSFETs.
Claim 20
Dependent Claim
16 words
The regulator circuit of claim 1 wherein said main and synchronous switching elements comprise bipolar transistors.
Claim 21
Dependent Claim
15 words
The regulator circuit of claim 1 wherein said regulator circuit is in a step-down configuration.
Claim 22
Dependent Claim
15 words
The regulator circuit of claim 1 wherein said regulator circuit is in a boost configuration.
Claim 23
Dependent Claim
15 words
The regulator circuit of claim 1 wherein said regulator circuit is in a buck-boost configuration.
Claim 24
Independent Claim
124 words
A method of regulating current supplied to a load by a synchronous switching regulator, said regulator comprising control circuitry for controlling the regulator's duty cycle, output circuitry coupled to said control circuitry and to said load, said output circuitry comprising an inductor, a main switching element that causes current in said inductor to increase, a synchronous switching element that conducts said inductor current when said main switching element is non-conductive, and voltage-drop sensing circuitry coupled to said synchronous switching element and to said control circuitry, said method comprising the steps of: sensing the voltage drop across said synchronous switching element when said synchronous switching element is conductive; deriving current information from said sensing; and varying said duty cycle in response to said current information.
Claim 25
Independent Claim
124 words
A method of regulating current supplied to a load by a synchronous switching regulator, said regulator comprising control circuitry for controlling the regulator's duty cycle, output circuitry coupled to said control circuitry and to said load, said output circuitry comprising an inductor, a main switching element that causes current in said inductor to increase, a synchronous switching element that conducts said inductor current when said main switching element is non-conductive, and voltage-drop sensing circuitry coupled to said synchronous switching element and to said control circuitry, said method comprising the steps of: sensing the voltage drop across said synchronous switching element when said synchronous switching element is conductive; deriving current information from said sensing; and varying said duty cycle in response to said current information.
Claim 26
Dependent Claim
26 words
The method of claim 23 wherein said step of sensing further comprises the step of: inhibiting said sensing step when said synchronous switching element is non-conducting.
Claim 27
Dependent Claim
20 words
The method of claim 24 wherein said synchronous switching element is conducting during at least a portion of each cycle.
Claim 28
Dependent Claim
37 words
The method of claim 23 wherein said step of sensing further comprises the steps of: sensing the voltage drop across said main switching element; and summing said sensed voltage drops of said main and synchronous switching elements.
Claim 29
Dependent Claim
40 words
The method of claim 26 wherein said step of sensing the voltage drop across said main switching element further comprises the step of: inhibiting said sensing of said main switching element voltage drop when said main switching element is non-conducting.
Claim 30
Dependent Claim
30 words
The method of claim 26 wherein said step of deriving comprises the steps of: deriving an analog signal waveform indicative of said current; and smoothening said current analog signal waveform.
Claim 31
Independent Claim
144 words
A method of protecting a synchronous switching regulator from damage when a fault occurs, said regulator providing current to a load and comprising control circuitry for controlling the regulator's duty cycle, output circuitry coupled to said control circuitry and to said load, said output circuitry comprising an inductor, a main switching element that causes current in said inductor to increase, a synchronous switching element that conducts said inductor current when said main switching element is non-conductive, and voltage-drop sensing circuitry coupled to said synchronous switching element and to said control circuitry, said method comprising the steps of: sensing the voltage drop across said synchronous switching element when said synchronous switching element is conductive; deriving a signal from said sensing indicative of an amount of current being supplied by said regulator; and reducing the duty cycle of said regulator if said signal exceeds a threshold.
Claim 32
Independent Claim
144 words
A method of protecting a synchronous switching regulator from damage when a fault occurs, said regulator providing current to a load and comprising control circuitry for controlling the regulator's duty cycle, output circuitry coupled to said control circuitry and to said load, said output circuitry comprising an inductor, a main switching element that causes current in said inductor to increase, a synchronous switching element that conducts said inductor current when said main switching element is non-conductive, and voltage-drop sensing circuitry coupled to said synchronous switching element and to said control circuitry, said method comprising the steps of: sensing the voltage drop across said synchronous switching element when said synchronous switching element is conductive; deriving a signal from said sensing indicative of an amount of current being supplied by said regulator; and reducing the duty cycle of said regulator if said signal exceeds a threshold.
Claim 33
Dependent Claim
22 words
The method of claim 29 further comprising the step of: skipping cycles of said regulator until said threshold is no longer exceeded.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2001-12-07 | 2002-06-08 | 2002-12-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-12-07 | 2006-06-08 | 2006-12-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-12-07 | 2010-06-08 | 2010-12-08 | $7700.00 | Window Closed / Lapsed |