Current-mode control for switched step up-step down regulators
First Claim
1. A regulator circuit for step-up and step-down operation having an input connectable to a power source and an output connectable to a load, the regulator circuit comprising:
- an inductor;
a first controlled switch connected between a first inductor terminal and an input terminal;
a second controlled switch connected between the first inductor terminal and a common connection;
a third controlled switch connected between the second inductor terminal and the common connection;
a fourth controlled switch connected between the second inductor terminal and an output terminal; and
a control circuit coupled to a source of constant frequency clock cycles;
whereinthe control circuit is responsive to receipt of each clock pulse of the clock source to activate one of the controlled switches and deactivate another of the controlled switches and is responsive to current in the inductor attaining a current threshold during each clock cycle to reverse the switch activation and deactivation states for the remainder of the clock cycle.
3 Assignments
0 Petitions
Accused Products
Abstract
A switched regulator circuit provides step-up and step-down operation in which the level of the input voltage can be greater, equal to, or less than a preset controlled output voltage. A four switch arrangement or two switch arrangement provides buck, boost, and buck-boost regulation under constant frequency valley-peak current mode control. A single sense resistor may be utilized for sensing inductor current during only a short period during each duty cycle. As an alternative to the sense resistor, the switches themselves can be used to sense current during operation.
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Citations
12 Claims
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1. A regulator circuit for step-up and step-down operation having an input connectable to a power source and an output connectable to a load, the regulator circuit comprising:
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an inductor; a first controlled switch connected between a first inductor terminal and an input terminal; a second controlled switch connected between the first inductor terminal and a common connection; a third controlled switch connected between the second inductor terminal and the common connection; a fourth controlled switch connected between the second inductor terminal and an output terminal; and a control circuit coupled to a source of constant frequency clock cycles;
whereinthe control circuit is responsive to receipt of each clock pulse of the clock source to activate one of the controlled switches and deactivate another of the controlled switches and is responsive to current in the inductor attaining a current threshold during each clock cycle to reverse the switch activation and deactivation states for the remainder of the clock cycle. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A regulator circuit for step-up and step down operation having an input connectable to a power source and an output connectable to a load, the regulator circuit comprising:
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an inductor; a first switch connected between a first inductor terminal and an input terminal; a second switch connected between the first inductor terminal and a common connection; a third switch connected between the second inductor terminal and the common connection; a fourth switch connected between the second inductor terminal and an output terminal; and a control circuit responsive to current in the inductor for controlling activation and deactivation of the switches to regulate voltage at the output to a preset voltage, wherein the control circuit comprises; comparator circuitry; a logic circuit connected to the comparator circuitry to receive input therefrom; and switch driver circuitry responsive to the logic circuit for controlling the states of the switches; and
wherein the comparator circuitry comprises;an error amplifier having a first input for receiving a voltage proportional to the voltage at the output terminal and a second input for receiving a reference potential to produce a difference signal representing the difference therebetween; and a differential circuit responsive to the difference signal and an inductor current sensing element, the differential circuit connected to the logic circuit; and wherein the differential circuit comprises a first circuit section for receiving a signal output from the current sensing element and a second circuit section for receiving the signal output from the current sensing element with inverted polarity.
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9. A regulator circuit
for step-up and step-down operation having an input connectable to a power source and an output connectable to a load, the regulator circuit comprising: -
an inductor; a first switch connected between a first inductor terminal and an input terminal; a second switch connected between the first inductor terminal and a common connection; a third switch connected between the second inductor terminal and the common connection; a fourth switch connected between the second inductor terminal and an output terminal; and a control circuit responsive to current in the inductor and a voltage proportional to output voltage for controlling activation and deactivation of the switches to regulate voltage at the output to a preset voltage that is approximately the same as the input voltage during steady state buck-boost mode operation;
whereinthe first switch and the second switch are controlled to be in reciprocal conductive states to one another; the third switch and the fourth switch are controlled to be in reciprocal conductive states to one another; and the first switch and the fourth switch are in a closed state for a majority of time during each operating cycle of cycled operation; and each operating cycle begins in response to a clock signal and, at the beginning of each cycle, the second and fourth switches are turned on for respective portions of the operating cycle followed by turn on of the first switch and turn on of the third switch for a brief portion of the same operating cycle prior to turn on of the fourth switch for the remainder of the same operating cycle. - View Dependent Claims (10)
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11. A regulator circuit
for step-up and step-down operation having an input connectable to a power source and an output connectable to a load, the regulator circuit comprising: -
an inductor; a first switch connected between a first inductor terminal and an input terminal; a second switch connected between the first inductor terminal and a common connection; a third switch connected between the second inductor terminal and the common connection; a fourth switch connected between the second inductor terminal and an output terminal; and a control circuit responsive to current in the inductor and a voltage proportional to output voltage for controlling activation and deactivation of the switches to regulate voltage at the output to a preset voltage that is approximately the same as the input voltage during steady state buck-boost mode operation;
whereinthe first switch and the second switch are controlled to be in reciprocal conductive states to one another; the third switch and the fourth switch are controlled to be in reciprocal conductive states to one another; and the first switch and the fourth switch are in a closed state for a majority of time during each operating cycle of cycled operation; and each operating cycle begins in response to a clock signal and, at the beginning of each cycle, the first and third switch are turned on for respective portions of the operating cycle followed by turn on of the second switch for a brief portion of the same operating cycle and turn on of the fourth switch for the remainder of the same operating cycle. - View Dependent Claims (12)
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Specification