Switching regulators with ripple-based control (ie, ?ripple regulators?) are conceptually simple, have fast transient responses to both line and load perturbations, and some versions operate with a switching frequency that is proportional to the load current under the discontinuous conduction mode These characteristics make the ripple regulators well-suited, especially for power management applications in computers and portable electronic devices Ripple regulators also have some drawbacks, including (in some versions) a poorly defined switching frequency, noise-induced jitter, inadequate dc regulation, and a tendency for fast-scale instability This paper presents an overview of the various ripple-based control techniques, discusses their merits and limitations, and introduces techniques for reducing the noise sensitivity and the sensitivity to capacitor parameters, improving the frequency stability and the dc regulation, and avoiding fast-scale instability

Ripple-Based Control of Switching Regulators—An Overview

A light emitting diode (LED) lighting system includes a PFC and output voltage controller and a LED lighting power system. The controller advantageously operates from an auxiliary voltage less than a link voltage generated by the LED lighting power system. The common reference voltage allows all the components of lighting system to work together. A power factor correction switch and an LED drive current switch are coupled to the common reference node and have control node-to-common node, absolute voltage that allows the controller to control the conductivity of the switches. The LED lighting system can utilize feed forward control to concurrently modify power demand by the LED lighting power system and power demand of one or more LEDs. The LED lighting system can utilize a common current sense device to provide a common feedback signal to the controller representing current in at least two of the LEDs.

Power control system for current regulated light sources

An apparatus and method for converting a capacitance measured on a sensor element to a digital code. The apparatus may include a switching capacitor as a sensor element of a sensing device, and a sigma-delta modulator coupled to the sensor element to convert a capacitance measured on the sensor element to a digital code. The switching capacitor is in a feedback loop of the sigma-delta modulator. The method may include measuring a capacitance on a sensor element of a sensing device using a sigma-delta modulator, and converting the capacitance measured on the sensor element to a digital code.

Capacitance to code converter with sigma-delta modulator

An apparatus, method, and system are provided for power conversion to supply power to a load such as a plurality of light emitting diodes. An exemplary apparatus comprises: a first power converter stage having a first power switch and a first inductive element; a second power converter stage having a second power switch and a second inductive element; a plurality of sensors; and a controller. The second power converter stage provides an output current to the load. The controller is adapted to use a sensed input voltage to determine a switching period, and is further adapted to turn the first and second power switches into an on-state at a frequency substantially corresponding to the switching period while maintaining a switching duty cycle within a predetermined range.

Apparatus, System and Method for Cascaded Power Conversion

In at least one embodiment, a controller allows triac-based dimmer to properly function and dim a load whose voltage is regulated by a switching power converter. In at least one embodiment, the switching power converter includes a switch to control voltage conversion of an input voltage to the switching power converter, wherein phase delays are introduced in the input voltage by a triac-based dimmer during a dimming period. In at least one embodiment, the controller is configured to control the switch of the switching power converter to establish an input resistance of the switching power converter during a dimming portion of the input voltage, wherein the input resistance allows the triac-based dimmer to phase modulate a supply voltage to the dimmer so that an output voltage of the dimmer has a substantially uninterrupted phase delay during each half-cycle of the supply voltage during the dimming period.

Switching power converter control with triac-based leading edge dimmer compatibility

A method and circuit enable a voltage regulator to employ the smallest possible output capacitor that allows the regulator's output voltage to be maintained within specified boundaries for large bidirectional step changes in load current. This is achieved with a technique referred to as “optimal voltage positioning”, which keeps the output voltage within the specified boundaries while employing an output capacitor which has a combination of the largest possible equivalent series resistance (ESR) and lowest possible capacitance that ensures that the peak voltage deviation for a step change in load current is no greater than the maximum allowed. The invention can be used with regulators subject to design requirements that specify a minimum time T min between load transients, and with those for which no T min is specified. When no T min is specified, optimal voltage positioning is achieved by compensating the regulator to ensure a response that is flat after the occurrence of the peak deviation, which enables the output voltage to remain within specified limits regardless of how quickly load transients occur. Another embodiment enables the power consumption of the device being powered by the regulator to be reduced under certain circumstances, while still employing the smallest possible output capacitor that allows the regulator's output voltage to be maintained within specified boundaries. The invention is applicable to both switching and linear voltage regulators.

Voltage regulator compensation circuit and method

A switched noise filter circuit for DC-DC converters which use the instantaneous output voltage to establish the converter’s duty ratio. The converter cycles the switching element on and off for time intervals Ton and Toff, respectively. A switching control circuit (40) includes a filter capacitance (Cf) connected between the feedback node (42) and ground, and a comparator (A1) which compares a feedback voltage Vfb with a fixed voltage Vref; at least one of Ton and Toff is a “modulated” interval which is terminated when Vfb crosses Vref due to the discharge of the filter capacitance. A switched noise filter circuit (46) applies an offset voltage to Vfb during at least one of Ton and Toff, with the offset voltage disconnected from Vfb by the beginning of the modulated interval or shortly thereafter. When the offset voltage is properly applied, the effect of extraneous electromagnetic noise coupled into Vfb is reduced.

Switched noise filter circuit for a DC-DC converter

PROBLEM TO BE SOLVED: To minimize the capacitor size by maintaining the regulator's output voltage within specified boundaries for large bi-directional step change in load current. SOLUTION: A current sensor 64 at a controllable power stage 50 generates an output signal which varies along with the output current from the power stage 50. A current controller 66 receives the output signal thus generated along with the output 62 from a voltage error amplifier 59 to produce an output 67. In response to the output 67 from the current controller 66, a power circuit 68 generates an output voltage Vout. The output capacitor 56 of the power circuit 68, i.e., a regulator, maintains the output voltage within a boundary specified for the bi-directional step change in load current. Consequently, the capacitor size is minimized and the power circuit 68 can be compensated.

Method and circuit for improving voltage regulator load transient response and minimizing output capacitor size

A digital blanking circuit allows a first digital input signal transition to be passed on to a following stage, but prohibits the passing of subsequent transitions for a predetermined blanking interval. One embodiment of the present invention employs rising edge and falling edge latches, the inputs of which receive the digital input signal and the outputs of which are connected to a two-to-one multiplexer. The mux output is connected to a blanking interval circuit, which is triggered to begin timing a blanking interval by a multiplexer output transition. The blanking interval circuit provides outputs which control the latches and selects the latch output to be transferred to the multiplexer output such that the multiplexer output is prevented from transitioning during a blanking interval. An “adaptive” blanking circuit is also described in which the blanking interval is terminated when the transition which triggered the start of the blanking interval propagates through an entire signal path, such that the blanking interval is automatically adjusted to be the same as the signal path delay.

Digital blanking circuit

This paper focuses on the power management solutions for desktop and mobile CPUs, with special emphasis on the control aspects and the related control IC requirements and architectures for VRM applications. The paper discusses the following topics: power converter topologies, load transient response, the ADOPTTM voltage positioning technology, maintaining high efficiency over a wide loadcurrent range, current and thermal balancing, current-sense solutions, protection functions, functional block schematics of VRM control ICs, and challenges for the IC designers.

Gabor Reizik

Papers

Voltage regulator compensation circuit and method

Switched noise filter circuit for a DC-DC converter

Method and circuit for improving voltage regulator load transient response and minimizing output capacitor size

Digital blanking circuit

Power Management Solutions for Desktop and Mobile CPUS