EP0415244A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Adaptive compensating ramp generator for current-mode DC/DC converters
Assignee: National Semiconductor Corp
•
Filing: 1990-08-22
•
Granted: —
•
Expires: 2010-08-22
Abstract
Abstract A circuit (20, 40, 50, 60) for generating an optimal compensating ramp voltage signal V cramp , with the minimum necessary slope, m c for a current mode DC/DC converter is shown. The adaptive compensating ramp generating circuit (20) is comprised of two voltage dividers (22, 24), the first voltage divider 22 divides an input voltage V IN and the second voltage divider 24 divides an output voltage V OUT . The first voltage divider (22) has two resistors (26, 28) in series: the first resistor (26) has a resistance of (1/B - 1) * R ohms and the second resistor (28) has a resistance of R ohms. V OUT is divided by the second voltage divider (24) having two resistors (29, 30) in series: the first resistor (29) has a resistance of (1/A - 1) * R ohms and the second resistor (30) has a resistance of R ohms. The constants A, B, and C are selected for the particular type of DC/DC converter employed. The divided voltages A * V OUT and B * V IN are input into a voltage controlled current source (32). The voltage controlled current source (32) has a scaling resistor R scale , an amplifier (36), a transistor Q, and a diode D1. The output of the current source (38) is coupled to a capacitor C ramp whose voltage realizes the slope of the compensating ramp signal, V cramp . The capacitor C ramp is charged through R scale .
Inventors
- 👤 Tamas S. Szepesi
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-01 13:26
CPC Classifications
H; H02; H02M; H02M3/00; H02M3/22; H02M3/24; H02M3/28; H02M3/325; H02M3/335; H02M3/33507; H02M3/02; H02M3/04; H02M3/10; H02M3/145; H02M3/155; H02M3/156
Claims Analysis
Total Claims: 43
Claim 1
Independent Claim
172 words
A circuit for generating a compensating ramp in a switching regulator of the type which is responsive to an unregulated input voltage (V IN ) and which provides a regulated output voltage (V OUT ), having a controlled switching element further having a sense resistor (R s ) which provides a signal proportional to the current flowing through the switching element, the signal being used to control the operation of the switching regulator, and means for storing energy having an inductance (L), the compensating ramp circuit comprising: means for generating a compensating ramp voltage having a slope (m c ) which conforms to the equation m c ≧ (A * V o - B * V IN ) * C where A ≦ 1 B ≦ 1 C is a constant dependent upon R s , L and magnetic coupling parameters associated with the energy storage means; and means for superimposing the generated compensating ramp voltage onto the signal from the sense resistor whereby the stability of the switching regulator is maintained.
Claim 2
Dependent Claim
172 words
A circuit for generating a compensating ramp in a switching regulator of the type which is responsive to an unregulated input voltage (V IN ) and which provides a regulated output voltage (V OUT ), having a controlled switching element further having a sense resistor (R s ) which provides a signal proportional to the current flowing through the switching element, the signal being used to control the operation of the switching regulator, and means for storing energy having an inductance (L), the compensating ramp circuit comprising: means for generating a compensating ramp voltage having a slope (m c ) which conforms to the equation m c ≧ (A * V o - B * V IN ) * C where A ≦ 1 B ≦ 1 C is a constant dependent upon R s , L and magnetic coupling parameters associated with the energy storage means; and means for superimposing the generated compensating ramp voltage onto the signal from the sense resistor whereby the stability of the switching regulator is maintained.
Claim 3
Dependent Claim
43 words
The circuit of Claim 1, wherein A, B, C are selected according to the type of switching regulator as follows: Switching Regulator A B C Buck 1 ≦.5 2R s /L Boost ≧.5 1 2R s /L Buck-Boost 1 ≦1 R s /L
Claim 4
Dependent Claim
35 words
The circuit of Claim 1, wherein the switching regulator is a buck converter and A is equal to about one, B is equal to about one-half, and C is equal to about 2*R s /L.
Claim 5
Dependent Claim
35 words
The circuit of Claim 1, wherein the switching regulator is a boost converter and A is about equal to one-half, B is about equal to one, and C is about equal to 2*R s /L.
Claim 6
Dependent Claim
53 words
The circuit of Claim 1, wherein the means for storing energy is a transformer having a primary winding of n p turns, a secondary winding of n s turns, and a turns ratio of n, where n= ns /n p , and the inductance of the energy storing means is L p .
Claim 7
Dependent Claim
62 words
The circuit of Claim 5, wherein A, B, and C are selected according to the type of switching regulator as follows: Switching Regulator A B C Flyback n > 1 ≧1/n 1 R s /L p n < 1 1 ≦n R s /nL p Forward n > 2 ≧2/n 1 n²R s /L n < 2 1 ≦n/2 2nR s /L
Claim 8
Dependent Claim
45 words
The circuit of Claim 5, wherein the switching regulator is a flyback converter and n is greater than about one such that A is about equal to 1/n, B is about equal to one, and C is about equal to R s /L p .
Claim 9
Dependent Claim
45 words
The circuit of Claim 5, wherein the switching regulator is a flyback converter and n is less than about one such that A is about equal to one, B is about equal to n, and C is about equal to R s /(n*L p ).
Claim 10
Dependent Claim
43 words
The circuit of Claim 5, wherein the switching regulator is a forward converter and n is greater than about two such that A is about equal to 2/n, B is about equal to 1, and C is about equal to n²*R s /L.
Claim 11
Dependent Claim
43 words
The circuit of Claim 5, wherein the switching regulator is a forward converter and n is less than about two such that A is about equal to one, B is about equal to n/2, and C is about equal to 2*n*R s /L.
Claim 12
Dependent Claim
35 words
The circuit of Claim 1, wherein the switching regulator is a buck-boost converter and A is about equal to one, B is about equal to one, and C is about equal to R s /L.
Claim 13
Independent Claim
205 words
A method for generating a compensating ramp signal having a slope (m c ) in a switching regulator of the type which is responsive to an unregulated input voltage (V IN ) and which provides a regulated output voltage (V OUT ), having a sense resistor (R s ) which provides a signal proportional to the current flowing through a controlled switching element, the signal being used to control the operation of the switching regulator, and means for storing energy having an inductance (L), comprising the steps of: (A). generating a first voltage proportional to the output voltage; (B). generating a second voltage proportional to the input voltage, wherein the proportion for the first voltage and the proportion for the second voltage are selected based upon the type of switching circuit; (C). taking the difference between the first and second voltages and multiplying the difference by a factor determined by R s , L and magnetic coupling parameters associated with the energy storage means to generate the compensating ramp voltage with a slope that is about equal to the multiplied difference; and (D). superimposing the generated compensating ramp voltage onto the signal from the sense resistor whereby the stability of the switching regulator is enhanced.
Claim 14
Independent Claim
205 words
A method for generating a compensating ramp signal having a slope (m c ) in a switching regulator of the type which is responsive to an unregulated input voltage (V IN ) and which provides a regulated output voltage (V OUT ), having a sense resistor (R s ) which provides a signal proportional to the current flowing through a controlled switching element, the signal being used to control the operation of the switching regulator, and means for storing energy having an inductance (L), comprising the steps of: (A). generating a first voltage proportional to the output voltage; (B). generating a second voltage proportional to the input voltage, wherein the proportion for the first voltage and the proportion for the second voltage are selected based upon the type of switching circuit; (C). taking the difference between the first and second voltages and multiplying the difference by a factor determined by R s , L and magnetic coupling parameters associated with the energy storage means to generate the compensating ramp voltage with a slope that is about equal to the multiplied difference; and (D). superimposing the generated compensating ramp voltage onto the signal from the sense resistor whereby the stability of the switching regulator is enhanced.
Claim 15
Dependent Claim
82 words
The method of Claim 12, wherein the switching regulator is a buck converter and, the first voltage generating step in step A includes setting the first voltage so that it is about equal to the input voltage, the second voltage generating step in step B includes setting the second voltage in step B so that it is about half the output voltage, and step C includes the step of setting the factor so that it is equal to about 2*R s /L.
Claim 16
Dependent Claim
79 words
The method of Claim 12, wherein the switching regulator is a boost converter and, the first voltage generating step in step A includes setting the first voltage so that it is about equal to one-half, the second voltage generating step in step B includes setting the second voltage in step B so that it is about equal to one, and step C includes the step of setting the factor so that it is about equal to 2*R s /L.
Claim 17
Dependent Claim
135 words
The method of Claim 12, wherein the means for storing energy is a transformer having a primary winding of n p turns, a secondary winding of n s turns, and a turns ratio of n, where n= n s /n p , the inductance of the energy storing means is L p , the switching regulator is a flyback converter where n is greater than about one, and the first voltage generating step in step A includes setting the first voltage so that it is about equal to 1/n, the second voltage generating step in step B includes setting the second voltage in step B so that it is about equal to one, and step C includes the step of setting the factor so that it is about equal to R s /L p .
Claim 18
Dependent Claim
134 words
The method of Claim 12, wherein the means for storing energy is a transformer having a primary winding of n p turns, a secondary winding of n s turns, and a turns ratio of n, where n= n n p , the inductance of the energy storing means is L p , the switching regulator is a flyback converter where n is less than about one, and the first voltage generating step in step A includes setting the first voltage so that it is about equal to one, the second voltage generating step in step B includes setting the second voltage in step B so that it is about equal to n, and step C includes the step of setting the factor so that it is about equal to R s /(n*L p ).
Claim 19
Dependent Claim
130 words
The method of Claim 12, wherein the means for storing energy is an inductor connected to the switching element via a transformer having a primary winding of n p turns, a secondary winding of n s , turns, and a turns ratio of n, where n=n s /n p , the switching regulator is a forward converter where n is greater than about two, and the first voltage generating step in step A includes setting the first voltage so that it is about equal to 2/n, the second voltage generating step in step B includes setting the second voltage in step B so that it is about equal to one, and step C includes the step of setting the factor so that it is about equal to n²*R s /L.
Claim 20
Dependent Claim
129 words
The method of Claim 12, wherein the means for storing energy is an inductor connected to the switching means via a transformer having a primary winding of n p turns, a secondary winding of n s turns, and a turns ratio of n, where n=n s /n p , the switching regulator is a forward converter where n is less than about two and the first voltage generating step in step A includes setting the first voltage so that it is about equal to one, the second voltage generating step in step B includes setting the second voltage in step B so that it is about equal to n/2, and step C includes the step of setting the factor so that it is about equal to 2*n*R s /L.
Claim 21
Dependent Claim
79 words
The method of Claim 12, wherein the switching regulator is a buck-boost converter and the first voltage generating step in step A includes setting the first voltage so that it is about equal to one, the second voltage generating step in step B includes setting the second voltage in step B so that it is about equal to one, and step C includes the step of setting the factor so that it is about equal to R s /L.
Claim 22
Dependent Claim
148 words
A circuit for generating a compensating ramp signal in a DC/DC converter, wherein the DC/DC converter receives an input voltage and provides an output voltage; has a sense resistor (R s ) which provides a signal proportional to the current flowing through a controlled switching element; and has means for storing energy having an inductance (L), wherein the circuit comprises: means responsive to the output voltage for providing a first signal which is equal to the output voltage divided by a first preselected amount; means responsive to the input voltage for providing a second signal which is equal to the input voltage divided by a second preselected amount; means for generating a charging current proportional to the difference between the first and second signals; and means responsive to the charging current for generating the ramp signal having a slope selected according to the particular type of DC/DC converter.
Claim 23
Dependent Claim
148 words
A circuit for generating a compensating ramp signal in a DC/DC converter, wherein the DC/DC converter receives an input voltage and provides an output voltage; has a sense resistor (R s ) which provides a signal proportional to the current flowing through a controlled switching element; and has means for storing energy having an inductance (L), wherein the circuit comprises: means responsive to the output voltage for providing a first signal which is equal to the output voltage divided by a first preselected amount; means responsive to the input voltage for providing a second signal which is equal to the input voltage divided by a second preselected amount; means for generating a charging current proportional to the difference between the first and second signals; and means responsive to the charging current for generating the ramp signal having a slope selected according to the particular type of DC/DC converter.
Claim 24
Dependent Claim
21 words
The circuit of Claim 20, wherein: the first preselected amount is ≦ 1 and the second preselected amount is ≦ 1.
Claim 25
Dependent Claim
20 words
The circuit of claim 20, wherein the means for generating the proportional charging current is a voltage controlled current source.
Claim 26
Dependent Claim
29 words
The circuit of claim 20, wherein the means responsive to the current includes a capacitive element having a value which is a function of R s , and L.
Claim 27
Dependent Claim
167 words
The circuit of claim 20 wherein the means for generating a current is comprised of: a first transistor means wherein the base of the first transistor means is connected to one of the means for dividing, the emitter of the first transistor means is biased to a first potential, and the collector is connected to a second potential such that the emitter base junction of the first transistor means is forward biased and the collector base junction is reverse biased; and a second transistor means having at least two collectors wherein the first collector of the second transistor means is connected to its base, the emitter of the second transistor means is connected to the emitter of the first transistor means, and the first collector of the second transistor means is connected to the other means for dividing via a scaling resistor, and the second collector of the second transistor means provides the proportional current to the means responsive to the current for generating the ramp signal.
Claim 28
Dependent Claim
140 words
The circuit of Claim 20, wherein the means for generating a current is comprised of: a first transistor means wherein the base of the first transistor is connected to the means for dividing which is connected to the input voltage, and the collector of the first transistor is connected to the input voltage; and a second transistor means having at least two collectors, the first collector of the second transistor means is connected to its base and to the first transistor emitter, the emitter of the second transistor means is connected to the other means for dividing which is connected to the output voltage via a scaling resistor, the other divider is selected so that the output voltage is unchanged, and the second collector provides the proportional current to the means responsive to the current for generating the ramp signal.
Claim 29
Dependent Claim
145 words
The circuit of claim 20 wherein the means for generating a current is comprised of: a first transistor means wherein the base of the first transistor means is connected to one of the means for dividing and the collector of the first transistor means is biased to a first potential and the emitter is biased to a second potential such that the emitter base junction of the first transistor means is forward biased; a second transistor means having at least two collectors wherein the first collector of the second transistor means is connected to its base and to the first transistor means emitter, the emitter of the second transistor means is connected to a third potential via a scaling resistor, and the second collector of the second transistor means provides the proportional current to the means responsive to the current for generating the ramp signal.
Claim 30
Dependent Claim
145 words
The circuit of Claim 20, wherein the means for generating a current is comprised of: a first transistor means wherein the base of the first transistor means is connected to the means for dividing which is connected to the output voltage, and the emitter of the first transistor means is connected to the output voltage via the second means for dividing; and a second transistor means having at least two collectors, the first collector of the second transistor means is connected to its base and to the input voltage via a scaling resistor, the emitter of the second transistor means is connected to the output voltage and to the first transistor means emitter, the other divider is selected so that the input voltage is unchanged, and the second collector provides the proportional current to the means responsive to the current for generating the ramp signal.
Claim 31
Dependent Claim
23 words
The circuit of Claim 25, wherein: the emitter of the second transistor means is connected to the output voltage through a scaling resistor.
Claim 32
Dependent Claim
53 words
The circuit of Claim 25, wherein: the means for generating a ramp signal includes means having a capacitance which is a function of L, and R s ; and the ramp signal is the voltage produced across the means having a capacitance when the proportional current is used to charge the capacitance means.
Claim 33
Dependent Claim
98 words
A circuit for generating a compensating ramp voltage in a DC/DC converter, the circuit receives an input voltage and an output voltage from the converter wherein the circuit comprises: means for dividing the output voltage by a first preselected amount; means for dividing the input voltage by a second preselected amount; means for generating a current proportional to the difference between the divided input voltage and the output voltage; and means for multiplying the difference of the first divided input voltage and the divided output voltage with a fixed slope ramp voltage, to generate the compensating ramp signal.
Claim 34
Dependent Claim
98 words
A circuit for generating a compensating ramp voltage in a DC/DC converter, the circuit receives an input voltage and an output voltage from the converter wherein the circuit comprises: means for dividing the output voltage by a first preselected amount; means for dividing the input voltage by a second preselected amount; means for generating a current proportional to the difference between the divided input voltage and the output voltage; and means for multiplying the difference of the first divided input voltage and the divided output voltage with a fixed slope ramp voltage, to generate the compensating ramp signal.
Claim 35
Independent Claim
205 words
A method for designing a compensating ramp signal having a slope (m c ) in a switching regulator of the type which is responsive to an unregulated input voltage (V IN ) and which provides a regulated output voltage (V OUT ), having a sense resistor (R s ) which provides a signal proportional to the current flowing through a controlled switching element, the signal being used to control the operation of the switching regulator, and means for storing energy having an inductance (L), comprising the steps of: (A). generating a first voltage proportional to the output voltage; (B). generating a second voltage proportional to the input voltage, wherein the proportion for the first voltage and the proportion for the second voltage are selected based upon the type of switching circuit; (C). taking the difference between the first and second voltages and multiplying the difference by a factor determined by R s , L and magnetic coupling parameters associated with the energy storage means to generate the compensating ramp voltage with a slope that is about equal to the multiplied difference; and (D). superimposing the generated compensating ramp voltage onto the signal from the sense resistor whereby the stability of the switching regulator is enhanced.
Claim 36
Independent Claim
205 words
A method for designing a compensating ramp signal having a slope (m c ) in a switching regulator of the type which is responsive to an unregulated input voltage (V IN ) and which provides a regulated output voltage (V OUT ), having a sense resistor (R s ) which provides a signal proportional to the current flowing through a controlled switching element, the signal being used to control the operation of the switching regulator, and means for storing energy having an inductance (L), comprising the steps of: (A). generating a first voltage proportional to the output voltage; (B). generating a second voltage proportional to the input voltage, wherein the proportion for the first voltage and the proportion for the second voltage are selected based upon the type of switching circuit; (C). taking the difference between the first and second voltages and multiplying the difference by a factor determined by R s , L and magnetic coupling parameters associated with the energy storage means to generate the compensating ramp voltage with a slope that is about equal to the multiplied difference; and (D). superimposing the generated compensating ramp voltage onto the signal from the sense resistor whereby the stability of the switching regulator is enhanced.
Claim 37
Dependent Claim
82 words
The method of Claim 31, wherein the switching regulator is a buck converter and, the first voltage generating step in step A includes setting the first voltage so that it is about equal to the input voltage, the second voltage generating step in step B includes setting the second voltage in step B so that it is about half the output voltage, and step C includes the step of setting the factor so that it is equal to about 2*R s /L.
Claim 38
Dependent Claim
79 words
The method of Claim 31, wharein the switching regulator is a boost converter and, the first voltage generating step in step A includes setting the first voltage so that it is about equal to one-half, the second voltage generating step in step B includes setting the second voltage in step B so that it is about equal to one, and step C includes the step of setting the factor so that it is about equal to 2*R s /L.
Claim 39
Dependent Claim
135 words
The method of Claim 31, wherein the means for storing energy is a transformer having a primary winding of n p turns, a secondary winding of n s , turns, and a turns ratio of n, where n=n s /n p , the inductance of the energy storing means is L p , the switching regulator is a flyback converter where n is greater than about one, and the first voltage generating step in step A includes setting the first voltage so that it is about equal to 1/n, the second voltage generating step in step B includes setting the second voltage in step B so that it is about equal to one, and step C includes the step of setting the factor so that it is about equal to R s /L p .
Claim 40
Dependent Claim
134 words
The method of Claim 31, wherein the means for storing energy is a transformer having a primary winding of n p turns, a secondary winding of n s turns, and a turns ratio of n, where n=n s /n p , the inductance of the energy storing means is L p , the switching regulator is a flyback converter where n is less than about one, and the first voltage generating step in step A includes setting the first voltage so that it is about equal to one, the second voltage generating step in step B includes setting the second voltage in step B so that it is about equal to n, and step C includes the step of setting the factor so that it is about equal to R s /(n*L p ).
Claim 41
Dependent Claim
129 words
The method of Claim 31, wherein the means for storing energy is an inductor connected to the switching element via a transformer having a primary winding of n p turns, a secondary winding of n s turns, and a turns ratio of n, where n=n s /n p , the switching regulator is a forward converter where n is greater than about two, and the first voltage generating step in step A includes setting the first voltage so that it is about equal to 2/n, the second voltage generating step in step B includes setting the second voltage in step B so that it is about equal to one, and step C includes the step of setting the factor so that it is about equal to n²*R s /L.
Claim 42
Dependent Claim
129 words
The method of Claim 31, wherein the means for storing energy is an inductor connected to the switching means via a transformer having a primary winding of n p turns, a secondary winding of n s turns, and a turns ratio of n, where n=n s /n p , the switching regulator is a forward converter where n is less than about two and the first voltage generating step in step A includes setting the first voltage so that it is about equal to one, the second voltage generating step in step B includes setting the second voltage in step B so that it is about equal to n/2, and step C includes the step of setting the factor so that it is about equal to 2*n*R s /L.
Claim 43
Dependent Claim
79 words
The method of Claim 31, wherein the switching regulator is a buck-boost converter and the first voltage generating step in step A includes setting the first voltage so that it is about equal to one, the second voltage generating step in step B includes setting the second voltage in step B so that it is about equal to one, and step C includes the step of setting the factor so that it is about equal to R s /L.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.