Hysteretic regulator and control method having switching frequency independent from output filter
First Claim
1. A DC to DC power converter, comprising:
- a first switch coupled to a second switch operating at a switching frequency, said converter adapted to receive an input voltage, generate an output voltage, and having an output filter coupled to said output voltage;
a first circuit generating a ramp signal comprising a first capacitor generating said ramp signal at one end; and
a hysteretic mode control circuit having an output coupled to said first and second switches and having an input coupled to said output filter and to said first circuit, said hysteretic mode control circuit controlling said switching frequency of said first and second switch as a function of said ramp signal.
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Accused Products
Abstract
A DC to DC power converter (58) and method of controlling the DC to DC power converter (58). The converter (58) has a first switch (S1) coupled to a second switch (S2). The converter (58) is adapted to receive an input voltage Vin, generate an output voltage Vout, and operate at a switching frequency. A hysteretic mode control circuit (52) includes a first circuit generating a ramp signal at input (56) for controlling the converter (58). The first circuit includes a first capacitor (C1) with the ramp signal generated at an end of the first capacitor (C1). The hysteretic mode control circuit (52) is coupled to the first (S1) and second (S2) switches, where the switching frequency of the first and second switches is dependent upon the ramp signal (56) determined by the value of the components of the first circuit rather than on the voltage from the output filter of the DC to DC power converter. The invention is particularly useful for applications such as DSPs and mixed signal or analog circuits.
211 Citations
22 Claims
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1. A DC to DC power converter, comprising:
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a first switch coupled to a second switch operating at a switching frequency, said converter adapted to receive an input voltage, generate an output voltage, and having an output filter coupled to said output voltage; a first circuit generating a ramp signal comprising a first capacitor generating said ramp signal at one end; and a hysteretic mode control circuit having an output coupled to said first and second switches and having an input coupled to said output filter and to said first circuit, said hysteretic mode control circuit controlling said switching frequency of said first and second switch as a function of said ramp signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A DC to DC power converter, comprising:
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a first switch coupled to a second switch operating at a switching frequency, said converter adapted to receive an input voltage, generate an output voltage, and having an output filter coupled to said output voltage, said output voltage having a ripple; a first circuit generating a ramp signal being greater than said output voltage ripple, said first circuit comprising a first capacitor having a first end and a second end, said ramp signal generated at said first capacitor second end; and a hysteretic mode control circuit having an output coupled to said first and second switches, and having an input coupled to said output filter and to said first circuit, the hysteretic mode control circuit controlling said switching frequency of said first and second switches as a function of said ramp signal such that said ripple of said output voltage is reduced. - View Dependent Claims (12, 13, 14, 15, 16, 17)
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18. A method of controlling an output voltage of a DC to DC power converter, said converter including a first switch coupled to a second switch operating at a switching frequency, said converter adapted to receive an input voltage and generate an output voltage, said converter having a hysteretic mode control circuit, said hysteretic mode control circuit having an output coupled to said first and second switches and having an input coupled to said output filter, said method comprising the steps of:
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generating a ramp signal using a first capacitor coupled to an input of said hysteretic mode control circuit; and controlling said switching frequency using said ramp signal wherein said switching frequency is dependent on the value of said first capacitor. - View Dependent Claims (19, 20, 21, 22)
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Specification