Abstract:
The present disclosure includes systems and methods for 100% duty cycle in switching regulators. A switching regulator circuit includes a ramp generator to produce a ramp signal having a period and a comparator to receive the ramp signal and an error signal, and in accordance therewith, produce a modulation signal. In a first mode of operation, the ramp signal increases to intersect the error signal, and in accordance therewith, changes a state of a switching transistor during each period of the ramp signal. In a second mode of operation, the error signal increase above a maximum value of the ramp signal, and in accordance therewith, the switching transistor is turned on for one or more full periods of the ramp signal.
Abstract:
Features and advantages of the present disclosure include a switching regulator and current measurement circuit. In one embodiment, a switching transistor in the switching regulator has a first voltage on a first terminal and a switching voltage on a second terminal. A current measurement circuit has first and second input terminals. A first switch couples the second terminal of the switching transistor to the first terminal of the current measurement circuit when the switching transistor is on, where the second input terminal of the current measurement circuit is coupled to the first terminal of the switching transistor and measurement(s) may be taken. When the switching transistor is off, the first and second input terminals of the current measurement circuit are coupled together, and measurements emulate zero current through the switching transistor.
Abstract:
In one embodiment, a circuit comprises a current source to produce current to a light emitting diode array. An analog dimming circuit generates a continuous control signal to the current source to control the current in the light emitting diode array according to a range of control signal values when the control signal is above a threshold. Below the threshold, a digital modulation circuit generates an additional modulated digital signal to the current source to control the current in the light emitting diode array according to a range of modulation values when the continuous control signal is below the threshold. The continuous control signal produces current from the current source into the light emitting diode array above a first value. The combination of the continuous control signal and the modulated digital signal produces current in the light emitting diode array below the first value.
Abstract:
A circuit for driving a load may include a control loop having a response characteristic. A headroom signal indicative of the headroom voltage of the circuit may set one or more parameters of the response characteristic. A load sign indicative of electrical loading on the circuit may further set the response characteristic.
Abstract:
Features and advantages of the present disclosure include a switching regulator and current measurement circuit. In one embodiment, a switching transistor in the switching regulator has a first voltage on a first terminal and a switching voltage on a second terminal. A current measurement circuit has first and second input terminals. A first switch couples the second terminal of the switching transistor to the first terminal of the current measurement circuit when the switching transistor is on, where the second input terminal of the current measurement circuit is coupled to the first terminal of the switching transistor and measurement(s) may be taken. When the switching transistor is off, the first and second input terminals of the current measurement circuit are coupled together, and measurements emulate zero current through the switching transistor.
Abstract:
A circuit may include a control loop to regulate an output of the circuit and a headroom sensing circuit to produce a headroom sensing signal indicative of a headroom voltage of the circuit. The control loop may have a response characteristic that is set based on the headroom signal received from the headroom sensing circuit.
Abstract:
Techniques and apparatus for driving a transistor gate of a switched-mode power supply (SMPS) circuit. One example gate driver for a switching transistor of an SMPS circuit generally includes a first power supply rail; a reference rail; an output node for coupling to a control input of the switching transistor; a floating supply node; a pulldown transistor having a drain coupled to the output node of the gate driver and having a source coupled to the reference rail; and a pulldown logic buffer having a first power supply input coupled to the floating supply node, having a second power supply input coupled to the reference rail, and having an output coupled to a gate of the pulldown transistor. The floating supply node is configured to selectively receive power from the first power supply rail and the output node of the gate driver.
Abstract:
A circuit may include a control loop to regulate an output of the circuit and a headroom sensing circuit to produce a headroom sensing signal indicative of a headroom voltage of the circuit. The control loop may have a response characteristic that is set based on the headroom signal received from the headroom sensing circuit.
Abstract:
A circuit for driving a load may include a control loop having a response characteristic. A headroom signal indicative of the headroom voltage of the circuit may set one or more parameters of the response characteristic. A load sign indicative of electrical loading on the circuit may further set the response characteristic.
Abstract:
In one embodiment, a circuit comprises a current source to produce current to a light emitting diode array. An analog dimming circuit generates a continuous control signal to the current source to control the current in the light emitting diode array according to a range of control signal values when the control signal is above a threshold. Below the threshold, a digital modulation circuit generates an additional modulated digital signal to the current source to control the current in the light emitting diode array according to a range of modulation values when the continuous control signal is below the threshold. The continuous control signal produces current from the current source into the light emitting diode array above a first value. The combination of the continuous control signal and the modulated digital signal produces current in the light emitting diode array below the first value.