Switch mode power supply with dynamic topology

A method of regulating an output voltage in response to an input voltage in a voltage regulator comprising an inductive element, comprising the steps of:

• operating the voltage regulator in a buck mode to reduce the input voltage if the input voltage is above the output voltage,
• operating the voltage regulator in a boost mode to increase the input voltage if the input voltage is below the output voltage,
• operating the voltage regulator in a solid-state flyback mode during switching between the buck mode and the boost mode, in the solid-state flyback mode, the inductive element being switched using switching devices between an input state in which the inductive device is connected between an input of the voltage regulator and a common node, and an output state in which the inductive element is connected between the common node and an output of the voltage regulator, and
• providing a mode control signal based on a duty cycle of a signal for controlling switching of the switching devices,
• wherein the duty cycle is compared with first, second, third and fourth threshold levels Dth1, Dth2, Dth3 and Dth4, respectively, where Dth1>Dth2>Dth3>Dth4.

A switching regulator for producing a regulated output voltage at an output node in response to an input voltage at an input node, comprising:

• an inductive device,
• a plurality of switching devices for providing connection of the inductive device to the input and output nodes and a common node,
• a switch driver circuit for driving the switching devices so as to enable the power supply to operate in a solid-state flyback mode, in which the switching devices are configured to provide switching of the inductive device between an input state in which the inductive device is connected between the input node and the common node, and an output state in which the inductive device is connected between the common node and the output node, and
• a duty cycle detection circuit for providing the switch driver circuit with a mode control signal based on a duty cycle of a signal for controlling switching of the switching devices,
• wherein the duty cycle detection circuit is configured for comparing the duty cycle with first, second, third and fourth threshold levels Dth1, Dth2, Dth3 and Dth4, respectively, where Dth1>Dth2>Dth3>Dth4.

A power supply system operating in a buck mode and in a boost mode for producing a regulated output signal at an output node in response to an input signal at an input node, comprising:

• an inductive device,
• a switching circuitry configured for providing connection of the inductive device to support operation in the buck mode and in the boost mode, the switching circuitry being configured to enable the system to operate in an intermediate mode of operation between the buck mode and the boost mode,
• an error amplifier for comparing the output voltage with a reference voltage to produce an error signal,
• a comparator responsive to the error signal and a peak current in the inductor to control the output signal,
• a transconductance control loop for controlling a relation between the peak current and an output signal of the error amplifier in accordance with a mode of operation, and
• a current sensor coupled to the inductive device for sensing the peak current in the inductive device, wherein the transconductance control loop includes a variable-gain amplifier coupled between the current sensor and the comparator, and having a gain adjusted when the system switches between the intermediate mode and the buck or boost mode.

A method of regulating an output voltage in response to an input voltage in a voltage regulator comprising an inductive element and an error amplifier for comparing the voltage signal with a reference voltage, comprising the steps of:

• operating the voltage regulator in a buck mode to reduce the input voltage if the input voltage is above the output voltage,
• operating the voltage regulator in a boost mode to increase the input voltage if the input voltage is below the output voltage,
• operating the voltage regulator in an intermediate mode during switching between the buck mode and the boost mode, and
• adjusting a relation between a peak current in the inductive element and an output signal of the error amplifier when the voltage regulator switches between the intermediate mode and the buck or boost mode,
• wherein the adjusting step includes adjusting a gain of an amplifier that amplifies a signal representing the peak current in the inductive element.

A power supply system operating in a buck mode and in a boost mode for producing a regulated output signal at an output node in response to an input signal at an input node, comprising:

• an inductive device,
• a switching circuitry configured for providing connection of the inductive device to support operation in the buck mode and in the boost mode, the switching circuitry being configured to enable the system to operate in an intermediate mode of operation between the buck mode and the boost mode,
• an error amplifier for comparing the output voltage with a reference voltage to produce an error signal,
• a comparator responsive to the error signal and a peak current in the inductor to control the output signal, and
• a transconductance control loop for controlling a relation between the peak current and an output signal of the error amplifier in accordance with a mode of operation,
• wherein the switching circuitry includes an input switching circuit coupled to connect the input node and the inductive device, and configured to produce a value representing a current flowing through the input switching circuit, and the transconductance control loop includes a variable-gain amplifier coupled between the input switching circuit and the comparator, and having a gain adjusted when the system switches between the intermediate mode and the buck or boost mode.

A method of regulating an output voltage in response to an input voltage in a voltage regulator comprising an inductive element and an error amplifier for comparing the voltage signal with a reference voltage, comprising the steps of:

• operating the voltage regulator in a buck mode to reduce the input voltage if the input voltage is above the output voltage,
• operating the voltage regulator in a boost mode to increase the input voltage if the input voltage is below the output voltage,
• operating the voltage regulator in an intermediate mode during switching between the buck mode and the boost mode, and
• adjusting a relation between a peak current in the inductive element and an output signal of the error amplifier when the voltage regulator switches between the intermediate mode and the buck or boost mode,
• wherein the adjusting step includes adjusting a gain of an amplifier that amplifies a signal representing a current in a switching circuit that connects an input of the voltage regulator to the inductive element.