Switched-mode power supply with bypass mode
AssigneeSTMicroelectronics (Alps) SAS
InventorPatrik Arno
Life of this patent
Estimating the term…
Abstract
In an embodiment, an SMPS comprises a half-bridge, and a driver configured to drive the half-bridge based on a PWM signal. The SMPS further comprising a first circuit coupled between the output of the driver and a control terminal of a high-side transistor of the half-bridge, wherein the first circuit is configured to maintain the first transistor on when the PWM signal has a duty cycle that is substantially 100%.
Claims22
A method of operating a switched-mode power supply, the method comprising:
- receiving a power supply voltage at a supply terminal;
- receiving a clock signal having a first frequency;
- receiving a pulse-width modulation (PWM) signal having the first frequency;
- operating the switched-mode power supply in a first mode, wherein operating the switched-mode power supply in the first mode comprises generating an output voltage at an output of the switched-mode power supply based on the PWM signal, wherein the output voltage is different than the power supply voltage;
- adjusting a resistance value of a feedback network of the switched-mode power supply;
- after adjusting the resistance value, counting a number of consecutive cycles of the clock signal in which the PWM signal does not switch;
- when the number of consecutive cycles of the clock signal in which the PWM signal does not switch reaches a first threshold, turning on a first transistor to cause the power supply voltage to be delivered to the output of the switched-mode power supply to operate the switched-mode power supply in a second mode;
- and
- stop switching the switched-mode power supply when operating the switched-mode power supply in the second mode.
A method of operating a switched-mode power supply having a switching mode and a bypass mode, the method comprising:
- receiving a power supply voltage at a supply terminal;
- receiving a clock signal having a first frequency;
- receiving a pulse-width modulation (PWM) signal having the first frequency;
- when the switched-mode power supply is in the switching mode, generating an output voltage at an output terminal of the switched-mode power supply based on the PWM signal;
- when the switched-mode power supply is in the bypass mode, connecting the supply terminal to the output terminal;
- and
- when transitioning from the switching mode to the bypass mode:
- changing the switched-mode power supply from a first state to a second state to cause a progressive change in the output voltage towards the power supply voltage,
- after changing the switched-mode power supply from the first state to the second state, counting a number of consecutive cycles of the clock signal in which the PWM signal does not switch, and
- when the number of consecutive cycles of the clock signal in which the PWM signal does not switch reaches a first threshold, connecting the supply terminal to the output terminal.
A method of operating a switched-mode power supply comprising a resistive feedback loop having an adjustable value, the method comprising:
- receiving a power supply voltage at a supply terminal;
- receiving a clock signal having a first frequency;
- receiving a pulse-width modulation (PWM) signal having the first frequency;
- when the switched-mode power supply is in a switching mode, generating an output voltage at an output terminal of the switched-mode power supply based on the PWM signal;
- when the switched-mode power supply is in a bypass mode, connecting the supply terminal to the output terminal;
- and
- when transitioning from the switching mode to the bypass mode:
- switching from a first state of the resistive feedback loop to a second state of the resistive feedback loop to cause a progressive change in the output voltage towards the power supply voltage.
Dependencies are inferred from the claim text.