Abstract: A switching circuit with reverse current prevention for use in a Buck converter includes a power switch coupled to a coupling node, which is an interconnection point of a power switch, an inductor and a freewheeling diode of the Buck converter. The inductor is coupled between the coupling node and an output of the Buck converter, and the freewheeling diode is coupled between coupling node and an output return of the Buck converter. A controller is coupled to receive a feedback signal to control switching of the power switch to regulate a transfer of energy from the input to the output of the Buck converter. A reverse current prevention circuit is coupled to detect a reverse current condition of the power switch to generate an inhibit signal to inhibit the power switch from receiving a drive signal to prevent a reverse current through the power switch.

Abstract: A controller for use in a power converter includes a first edge detection circuit that receives a first input sense signal representative of an input of the power converter coupled to a dimmer circuit, and generates a first edge detection signal in response to the first input sense signal. A shaping circuit receives the first edge detection signal from the first edge detection circuit. The shaping circuit generates a first shape signal in response to the first edge detection signal. A drive circuit receives the first shape signal and a feedback signal representative of an output of the power converter. The drive circuit generates the drive signal in response to the feedback signal to control switching of a power switch of the power converter. The drive circuit switches the power switch in a first higher current mode for a first duration in response to the first shape signal.

Abstract: A controller for a switched mode power converter includes limit-to-valley ratio circuitry, an on-time generator, and a drive circuit. The limit-to-valley ratio circuitry is coupled to generate a ratio signal in response to sensing a switch current of a switch that regulates an output of the switched mode power converter. The ratio signal is representative of a time ratio between a first length of time that the switch current is at or above a switch current limit and a second length of time that the switch current is at or below a switch current valley that is a portion of the switch current limit. The on-time generator is coupled to vary a switch on-time signal in response to receiving the ratio signal. The drive circuit is coupled to output a drive signal to a control terminal of the switch in response to receiving the switch on-time signal.

Abstract: A transient event detector includes a first reference generator, an adjustable low-pass filter, and a comparator. The first reference generator coupled to scale the input current signal to generate a first reference current signal that tracks the input current signal. The adjustable low-pass filter circuit is coupled to receive the input current signal and to generate a filtered input current signal such that a magnitude of a slope of the filtered input current signal is less than the magnitude of the slope of the input current signal during a transient event. The first comparator is coupled to generate an event detection signal that indicates the presence of the transient event in response to a value of the filtered input current signal reaching a value of the first reference current signal. The adjustable low-pass filter circuit is configured to increase the cutoff frequency in response to the event detection signal.

Abstract: A controller for use in a power converter includes a state selection circuit coupled to receive an input voltage sense signal representative of an input voltage, a switch current sense signal representative of a switch current of a power switch, and a feedback signal representative of an output quantity of the power converter. The state selection circuit is coupled to generate an input voltage signal in response to the input voltage sense signal, an input current signal in response to the switch current sense signal, and an input threshold signal in response to the feedback signal. A state machine circuit is coupled to the state selection circuit to generate a drive signal in response to the input voltage signal, the input current signal, and the input threshold signal to switch the power switch to control a transfer of energy from an input to an output of the power converter.

Abstract: A controller includes a multiplier block that is coupled to receive an input voltage signal, an input current signal, and an output voltage signal that are representative of a power conversion system. The multiplier block outputs a multiplier block output signal responsive to a product of the input voltage signal and the input current signal divided by the output voltage signal. A signal discriminator outputs a error signal responsive to the multiplier block output signal. The error signal is representative of a difference between a portion of the multiplier block output signal that is greater than a reference signal and a portion of the multiplier block output signal that is less than or equal to the reference signal. A switch controller generates a drive signal responsive to the error signal to control switching of a power switch to regulate an average output current of the power conversion system.

Abstract: A controller for a switched mode power converter includes limit-to-valley ratio circuitry, an on-time generator, and a drive circuit. The limit-to-valley ratio circuitry is coupled to generate a ratio signal in response to sensing a switch current of a switch that regulates an output of the switched mode power converter. The ratio signal is representative of a time ratio between a first length of time that the switch current is at or above a switch current limit and a second length of time that the switch current is at or below a switch current valley that is a portion of the switch current limit. The on-time generator is coupled to vary a switch on-time signal in response to receiving the ratio signal. The drive circuit is coupled to output a drive signal to a control terminal of the switch in response to receiving the switch on-time signal.

Abstract: A controller for controlling a power supply includes a feedback signal generator to generate a feedback signal representative of an output current in response to an output sense signal. A state selector circuit receives the feedback signal and outputs a digital state signal to set an operational state of a switch of the power supply. The state selector circuit adjusts the digital state signal in response to feedback information at an end of a feedback period. A driver circuit receives the digital state signal and generates a drive signal in response to the digital state signal. The drive signal drives switching of the switch in accordance with the operational state of the switch.

Abstract: A controller for use in a power converter includes a gate drive circuit coupled to generate a control signal to switch a power switch of the power converter. A zero current detection circuit is coupled to a multifunction pin coupled to receive a multifunction signal that is representative of an input voltage of the power converter when the power switch is on, and representative of an output voltage of the power converter when the power switch is off. The zero current detection circuit is coupled to generate a zero current detection signal. An overvoltage detection circuit is coupled to receive the multifunction signal and a state signal representative of a state of the power switch to generate in response to the state signal and the multifunction signal a line overvoltage signal and an output over voltage signal coupled to be received by the gate drive circuit.

Abstract: A controller for use in a power converter includes a gate drive circuit coupled to generate a control signal to switch a power switch of the power converter. A zero current detection circuit is coupled to a multifunction pin coupled to receive a multifunction signal that is representative of an input voltage of the power converter when the power switch is on, and representative of an output voltage of the power converter when the power switch is off. The zero current detection circuit is coupled to generate a zero current detection signal. An overvoltage detection circuit is coupled to receive the multifunction signal and a state signal representative of a state of the power switch to generate in response to the state signal and the multifunction signal a line overvoltage signal and an output over voltage signal coupled to be received by the gate drive circuit.

Abstract: Thermally protected bleeder circuits for maintaining an input current of a power converter above a dimmer circuit holding current are disclosed. In one example, a bleeder control circuit may generate a bleeder control signal to control a bleeder current of the bleeder circuit based on an input current signal and a temperature signal. The bleeder control circuit may cause the bleeder current to be substantially equal to zero in response to the input current signal being greater than or equal to a reference signal, and may cause the bleeder current to be proportional to a difference between the input current signal and the reference signal in response to the input current signal being less than the reference signal. The reference signal may be constant for temperatures less than a threshold temperature, but may decrease with respect to increases in temperature for temperatures greater than the threshold temperature.

Abstract: A switching circuit with reverse current prevention for use in a Buck converter includes a power switch coupled to a coupling node, which is an interconnection point of a power switch, an inductor and a freewheeling diode of the Buck converter. The inductor is coupled between the coupling node and an output of the Buck converter, and the freewheeling diode is coupled between coupling node and an output return of the Buck converter. A controller is coupled to receive a feedback signal to control switching of the power switch to regulate a transfer of energy from the input to the output of the Buck converter. A reverse current prevention circuit is coupled to detect a reverse current condition of the power switch to generate an inhibit signal to inhibit the power switch from receiving a drive signal to prevent a reverse current through the power switch.

Abstract: A bleeder controller for controlling a magnitude of a variable current conducted by bleeder circuitry between input terminals of a device is disclosed. The magnitude of the variable current is controllable in response to a control signal. The bleeder controller includes a dimming detector to classify a half line cycle as leading-edge-dimmed or a trailing-edge-dimmed in response to at least one of an input current sense signal and an input voltage sense signal.

Abstract: A power conversion device includes a power switch a first main terminal coupled to a higher potential portion, a second main terminal coupled to a lower potential portion, and a tap coupled to the first main terminal to provide a current for charging a supply terminal capacitor. A controller is coupled to a control terminal of the power switch to control switching of the power switch to produce a regulated output. A supply terminal is to be coupled to a supply terminal capacitor to store a charge for supplying power to at least some of the components of the controller. A voltage regulator is coupled to regulate the charge stored and a potential on the supply terminal capacitor. The current for charging the supply terminal capacitor is selectively drawn from the tap of the power switch in response to the supply terminal capacitor being below a threshold.

Abstract: A controller for a power converter includes conduction detection circuitry and a variable reference generator. The conduction detection circuitry is coupled to generate a conduction signal representative of conduction times that an input signal is above a threshold value. The variable reference generator is coupled to receive the conduction signal and configured to generate a count value in response to a first conduction time of the conduction signal. The variable reference generator is coupled to output a reference signal in response to the count value and in response to prior count values stored in the variable reference generator.

Abstract: A power converter controller asserts a leading edge signal when a leading edge of a voltage signal is detected. The voltage sense signal is representative of an input voltage of the power converter. A trailing edge signal is asserted when a trailing edge of the voltage signal is detected. A first state of a threshold signal is generated when the voltage sense signal is at or above an upper threshold and generating a second state of the threshold signal when the voltage sense signal is at or below a lower threshold. A conduction signal is updated in response to the leading edge signal, the trailing edge signal, and the threshold signal. The conduction signal is for controlling a switch coupled to regulate an output of the power converter.

Abstract: A controller for a power converter includes an edge detection circuit including a first circuit coupled to coupled to compare a voltage sense signal representative of an input voltage to a first reference, and a second circuit coupled to compare a current sense signal representative of an input current to a second reference. A slope sense circuit is coupled to measure a slope of the voltage sense signal over time. An edge driver circuit is coupled to generate an edge signal that indicates that an edge has been determined when the voltage sense signal is greater than the first reference, the current sense signal is lower than the second reference, and the slope is negative. A drive circuit is coupled to output a drive signal in response to the edge signal. The drive signal is for controlling a switch coupled to regulate an output of the power converter.

Abstract: A controller for a power converter includes an edge detection circuit and a drive circuit. The edge detection circuit includes a comparator, a count module, and an edge checking module. The comparator is coupled to output a compare signal in response to comparing an input sense signal and a count signal. The input sense signal is representative of an input voltage of the power converter. The count module is coupled to adjust the count signal to track the input sense signal in response to receiving the compare signal. The edge checking module is coupled to output at least one edge signal in response to the compare signal. The drive circuit is coupled to output a drive signal in response to the at least one edge signal. The drive signal is for controlling a switch coupled to regulate an output of the power converter.

Abstract: A controller includes a multiplier block that is coupled to receive an input voltage signal, an input current signal, and an output voltage signal that are representative of a power conversion system. The multiplier block outputs a multiplier block output signal responsive to a product of the input voltage signal and the input current signal divided by the output voltage signal. A signal discriminator outputs a error signal responsive to the multiplier block output signal. The error signal is representative of a difference between a portion of the multiplier block output signal that is greater than a reference signal and a portion of the multiplier block output signal that is less than or equal to the reference signal. A switch controller generates a drive signal responsive to the error signal to control switching of a power switch to regulate an average output current of the power conversion system.

Abstract: A power converter controller asserts a leading edge signal when a leading edge of a voltage signal is detected. The voltage sense signal is representative of an input voltage of the power converter. A trailing edge signal is asserted when a trailing edge of the voltage signal is detected. A first state of a threshold signal is generated when the voltage sense signal is at or above an upper threshold and generating a second state of the threshold signal when the voltage sense signal is at or below a lower threshold. A conduction signal is updated in response to the leading edge signal, the trailing edge signal, and the threshold signal. The conduction signal is for controlling a switch coupled to regulate an output of the power converter.