Wolfson Microelectronics Limited

Allegro Microsystems, LLC

Dialog Semiconductor (uk) Limited

Cirrus Logic International Semiconductor Limited

Andrew Notman

Mark McCloy-Stevens

Holger Haiplik

Douglas James Wallace MacFarlane

Guillaume De Cremoux

Vladislav Vasilev

Douglas Macfarlane

A power supply is disclosed. The power supply includes a switching converter for providing an output voltage comprising a power switch coupled to a driver for driving the power switch with an on-off switching cycle; and a voltage threshold indicator. The voltage threshold indicator includes an input for receiving an output of the converter, and an output coupled to the driver. The voltage threshold indicator is adapted to provide a temperature compensated voltage threshold, and a control signal to control the on-off switching cycle. The control signal is adapted such that when the output voltage exceeds the temperature compensated voltage threshold, a value of the control signal changes.

Switching power supply with low power consumption

Methods and apparatus for control of DC-DC converters, especially in valley current mode. The DC-DC converter is operable so that a low side supply switch may be turned off, before the high side supply switch is turned on. During the period when both switches are off the current loop control remains active and the change in inductor (L) current is emulated. One embodiment uses a current sensor for lossless current sensing and emulates the change in inductor current by holding the value of the output of the current sensor (ISNS) at the time that the low side switch turns off and adding an emulated ramp signal (VISLP) until the inductor current reaches zero. Embodiment employing a pulse-skip mode of operation based on a minimum conduction time are also disclosed. The invention enables a seamless transition from Continuous Conduction Mode the Discontinuous Conduction Mode and Pulse Skipping and provide converters that are efficient at low current loads.

DC-DC converters operable in a discontinuous switching mode

A regulator circuit comprising an input for receiving an input voltage; an output stage, configured to switch between said input voltage and a reference voltage to generate an output voltage, in dependence on a modulated signal; a controller, configured to receive an error signal (V) on a control input and to provide the modulated signal to said output stage; an error amplifier, for providing the error signal to the controller in dependence on the output voltage; and presetting circuitry, configured to estimate the error signal in dependence on at least the input voltage, and for presetting the control input with the estimated error signal.

Switched power regulator with error signal estimation and presetting

A level-shift circuit, comprising: an input, for receiving a first voltage; an output, for outputting a second voltage; a resistor array comprising one or more resistors connected in series to the input; a current sink for providing a current that is independent of the first voltage; a switch arrangement comprising a plurality of switch connections for establishing a selected one from a plurality of force paths between the current sink and the input, the selected force path comprising a selected number of the one or more resistors of said resistor array; and at least one connection between the output and the resistor array that provides a sense path between the resistor array and the output that does not comprise any of the switch connections used to establish each of the plurality of force paths.

Level-shifter circuit

Methods and apparatus for control of DC-DC converters. The DC-DC converter is operable so that the low side supply switch may be inhibited from turning on in a cycle following the high side supply switch turning off. Turn on of the low side switch is inhibited if the time between turn off of the high side switch and the inductor (L) current reaching zero is less than a predetermined duration. Inhibiting the low side switch from turning on can prevent the inductor current from going negative, which would reduce the efficiency of the converter. When turn on of the low side switch is inhibited the inductor current flows through a parallel path, such as a parasitic body diode associated with the low side switch, which allows current flow in one direction only.

DC-DC converter with low side switch control

A DC-to-DC converter generates multiple outputs from a single input supply using a single inductor. The inductor current can be changed rapidly by connecting the input voltage in either direction across the inductor using switches A to F. In use, current flows from the input supply through the inductor to an output during a charge phase, then current flows from ground through the inductor to the output in a discharge phase. The level of inductor current at the end of the discharge phase is stored. Before the next charge phase for the same output, the input supply is connected across the inductor in a slew phase to bring the inductor current to the stored level. This reduces crosstalk between outputs having different power requirements. Variable frequency noise in the converter is reduced by giving each output the same total time (slew phase+charge phase+discharge phase).

Multi-output DC-DC converter

A multi-mode switching regulator is capable of operating in a buck mode of operation, a boost mode of operation, and a buck-boost mode of operation. In the buck-boost mode of operation, the output voltage is regulated by adjusting a number of switch state transitions from a first state to a second state relative to a number of switch state transitions from the first state to a third state, and the duty cycle of each of the states is fixed from cycle to cycle in which the particular state occurs.

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Edinburgh, United Kingdom

Andrew Notman