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US 9,287,784 B2Granted
Adaptive biasing for integrated circuits
AssigneePower Integrations, Inc.
InventorsMichael Zhang, Yury Gaknoki, Mingming Mao
Life of this patent
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Abstract
Methods and apparatuses are disclosed for generating an adjustable bias current. The value of the adjustable bias current may be determined based in part on an error signal representative of a difference between an actual output value and a desired output value of a power converter. When the error signal is below a lower threshold voltage, the adjustable bias current may be set to a first value. When the error signal is above an upper threshold voltage, the adjustable bias current may be set to a second, higher value. When the error signal is between the lower threshold voltage and the upper threshold voltage, the adjustable bias current may change linearly with the error signal.
Claims23
An adjustable bias current generator circuit for use in a power converter, comprising:
- a reference current circuit coupled to generate a constant reference current, wherein the reference current circuit includes:
- a current source coupled to generate a constant current;
- and
- a first current mirror coupled to the current source, wherein the first current mirror includes a first transistor coupled to receive the constant current from the current source, and a second transistor coupled to the first transistor to generate the constant reference current;
- a comparison circuit coupled to the reference current circuit to generate an adjustable reference current, wherein the comparison circuit includes:
- a second current mirror including a third transistor coupled to the first and second transistors;
- a fourth transistor coupled to the third transistor;
- an impedance element coupled to the fourth transistor;
- a fifth transistor coupled to the impedance element, wherein the adjustable reference current is conducted through the fifth transistor, the impedance element, the fourth transistor, and the third transistor;
- a first operational amplifier having an output coupled to the fourth transistor, an inverting input coupled to receive a reference signal representative of a lower threshold voltage, and a non-inverting input coupled to a first end of the impedance element;
- and
- a second operational amplifier having an output coupled to the fifth transistor, an inverting input coupled to a second end of the impedance element, and a non-inverting element coupled to receive an error signal representative of a difference between an actual output value and a desired output value;
- and
- an output circuit coupled to the reference current circuit and the comparison circuit to generate the adjustable bias current, wherein the output circuit includes a third current mirror circuit including a sixth transistor coupled to a seventh transistor, wherein the reference current circuit and the comparison circuit are coupled to receive the constant reference current and the adjustable reference current from the sixth transistor, and wherein the seventh transistor is coupled to the sixth transistor to mirror a sum of the constant reference current and the adjustable reference current to generate the adjustable bias current.
11 more elements
A power converter comprising:
- a dc-dc converter coupled to receive an unregulated dc input voltage and output a regulated dc output voltage;
- and
- a controller coupled to the dc-dc converter and coupled to control the transfer of energy through the dc-dc converter, wherein the controller comprises:
- an amplifier operable to generate an error signal representative of a difference between an actual output value and a desired output value;
- and
- an adjustable bias current generator circuit, including:
- a reference current circuit coupled to generate a constant reference current, wherein the reference circuit includes:
- a current source coupled to generate a constant current;
- and
- a first current mirror coupled to the current source, wherein the first current mirror includes a first transistor coupled to receive the constant current from the current source, and a second transistor coupled to the first transistor to generate the constant reference current;
- a comparison circuit coupled to the reference current circuit to generate an adjustable reference current, wherein the comparison circuit includes:
- a second current mirror including a third transistor coupled to the first and second transistors;
- a fourth transistor coupled to the third transistor;
- an impedance element coupled to the fourth transistor;
- a fifth transistor coupled to the impedance element, wherein the adjustable reference current is conducted through the fifth transistor, the impedance element, the fourth transistor, and the third transistor;
- a first operational amplifier having an output coupled to the fourth transistor, an inverting input coupled to receive a reference signal representative of a lower threshold voltage, and a non-inverting input coupled to a first end of the impedance element;
- and
- a second operational amplifier having an output coupled to the fifth transistor, an inverting input coupled to a second end of the impedance element, and a non-inverting element coupled to receive an error signal representative of a difference between an actual output value and a desired output value;
- and
- an output circuit coupled to the reference current circuit and the comparison circuit to generate the adjustable bias current, wherein the output circuit includes a third current mirror circuit including a sixth transistor coupled to a seventh transistor, wherein the reference current circuit and the comparison circuit are coupled to receive the constant reference current and the adjustable reference current from the sixth transistor, and wherein the seventh transistor is coupled to the sixth transistor to mirror a sum of the constant reference current and the adjustable reference current to generate the adjustable bias current.
17 more elements
Dependencies are inferred from the claim text.