Abstract: During a light load (or no-load) operation of a totem pole power factor correction circuit (i.e., PFC), a pulse width modulation (PWM) controller can operate in a skip mode. Further, the PWM controller may disable portions of the PFC to reduce standby power consumption. In this mode, and in this disabled configuration, the output of the PFC may be peak charged over time to a voltage that could be damaging or destructive. This peak charging results from the PFC circuit's inability to fully charge/discharge EMI capacitors between half cycles of the input line voltage. The present disclosure provides circuits and methods to fully charge/discharge the EMI capacitors to prevent peak charging the output.

Abstract: A switched mode power supply controller includes a latch having an output for providing a drive signal, an off-time control circuit operating in valley switching and frequency reduction modes controlling an off-time of the latch based on at least a zero current detect signal, and an on-time control circuit resetting the latch in response to a current sense signal exceeding a feedback voltage representative of a load and to the current sense signal exceeding a modulated peak current threshold value. The on-time control circuit resets the latch in response to a current sense signal exceeding a feedback voltage representative of a load and to the current sense signal exceeding a peak current threshold value. In the frequency reduction mode, the on-time control circuit modulates the peak current threshold value by increasing the peak current threshold value by a predetermined amount.

Abstract: Bridgeless PFC converters. Example embodiments are methods of operating a power converter including operating the power converter during a positive half-line cycle of an alternating current (AC) source by: charging an inductance through a low-side switch with a first charging current having a first polarity; measuring the first charging current using a low-side current transformer (CT), while shorting a secondary winding of a high-side CT; and discharging the inductance through a high-side switch with a first discharging current having the first polarity. Operating the power converter during a negative half-line cycle of the AC source by: charging the inductance through the high-side switch with a second charging current having a second polarity; measuring the second charging current using the high-side CT, while shorting a secondary winding of the low-side CT; and discharging the inductance through the low-side switch with a second discharging current having the second polarity.

Abstract: Bridgeless PFC converters. Example embodiments are methods of operating a power converter including operating the power converter during a positive half-line cycle of an alternating current (AC) source by: charging an inductance through a low-side switch with a first charging current having a first polarity; measuring the first charging current using a low-side current transformer (CT), while shorting a secondary winding of a high-side CT; and discharging the inductance through a high-side switch with a first discharging current having the first polarity. Operating the power converter during a negative half-line cycle of the AC source by: charging the inductance through the high-side switch with a second charging current having a second polarity; measuring the second charging current using the high-side CT, while shorting a secondary winding of the low-side CT; and discharging the inductance through the low-side switch with a second discharging current having the second polarity.

Abstract: A switched mode power supply controller includes a latch having an output for providing a drive signal, an off-time control circuit operating in valley switching and frequency reduction modes controlling an off-time of the latch based on at least a zero current detect signal, and an on-time control circuit resetting the latch in response to a current sense signal exceeding a feedback voltage representative of a load and to the current sense signal exceeding a modulated peak current threshold value. The on-time control circuit resets the latch in response to a current sense signal exceeding a feedback voltage representative of a load and to the current sense signal exceeding a peak current threshold value. In the frequency reduction mode, the on-time control circuit modulates the peak current threshold value by increasing the peak current threshold value by a predetermined amount.

Abstract: Implementations of the present disclosure involve a circuit and/or method for a control circuit of a switched-mode power supply that allows the power supply circuit to temporarily provide up to 2.0× the nominal maximum power rating of the circuit without the need for large storage devices within the power supply. For example, a control circuit of a switched-mode power supply may cause the power supply to operate in a quasi-resonant mode. However, when the load on the circuit increases such that the feedback voltage measurement meets or exceeds a voltage threshold, the control circuit causes the switched-mode power supply to enter a power excursion mode with a fixed switching frequency. If the load on the switched-mode power supply continues to increase, the off time of the switched-mode power supply may be scaled in response to increase the power provided by the switched-mode power supply.

Abstract: Implementations of the present disclosure involve a circuit and/or method for a control circuit of a switched-mode power supply that allows the power supply circuit to temporarily provide up to 2.0× the nominal maximum power rating of the circuit without the need for large storage devices within the power supply. For example, a control circuit of a switched-mode power supply may cause the power supply to operate in a quasi-resonant mode. However, when the load on the circuit increases such that the feedback voltage measurement meets or exceeds a voltage threshold, the control circuit causes the switched-mode power supply to enter a power excursion mode with a fixed switching frequency. If the load on the switched-mode power supply continues to increase, the off time of the switched-mode power supply may be scaled in response to increase the power provided by the switched-mode power supply.

Abstract: Implementations of the present disclosure involve a circuit and/or method for a control circuit of a switched-mode power supply that allows the power supply circuit to temporarily provide up to 2.0× the nominal maximum power rating of the circuit without the need for large storage devices within the power supply. For example, a control circuit of a switched-mode power supply may cause the power supply to operate in a quasi-resonant mode. However, when the load on the circuit increases such that the feedback voltage measurement meets or exceeds a voltage threshold, the control circuit causes the switched-mode power supply to enter a power excursion mode with a fixed switching frequency. If the load on the switched-mode power supply continues to increase, the off time of the switched-mode power supply may be scaled in response to increase the power provided by the switched-mode power supply.

Abstract: Implementations of the present disclosure involve a circuit and/or method for a control circuit of a switched-mode power supply that allows the power supply circuit to temporarily provide up to 2.0× the nominal maximum power rating of the circuit without the need for large storage devices within the power supply. For example, a control circuit of a switched-mode power supply may cause the power supply to operate in a quasi-resonant mode. However, when the load on the circuit increases such that the feedback voltage measurement meets or exceeds a voltage threshold, the control circuit causes the switched-mode power supply to enter a power excursion mode with a fixed switching frequency. If the load on the switched-mode power supply continues to increase, the off time of the switched-mode power supply may be scaled in response to increase the power provided by the switched-mode power supply.

Abstract: A switched mode power supply (SMPS) receives an input voltage selectively connects and disconnects the input voltage from an inductor. The SMPS generates a charge in the inductor during a duty cycle portion while the input voltage is connected by generating control signals for selectively connecting to and disconnecting the input voltage from the inductor. Generating the control signals includes modulating a current source for a control capacitive element, selectively shorting the control capacitive element wherein a voltage VCT appears across the capacitive element when control capacitive element is not being shorted, and comparing voltage VCT to a threshold voltage generate an inverted DRIVE SIGNAL to selectively short the control capacitive element.