Dialog Semiconductor (UK) Limited

Analog Devices Global

Hirohisa Tanabe

Kenji Tomiyoshi

Seiichi Ozawa

Naoyuki Unno

Kohei Yamada

The disclosure provides for a slope voltage compensation circuit with an adaptive slope compensation method, in a DC-DC switching converter operating in current control mode, at duty cycles greater than 50%. The proposed solution allows for the dynamic range of useful operation to be extended, lowering the slope voltage compensation at the beginning of the cycle, and then increasing the compensation as 50% duty cycle is achieved. This method is based on voltage control instead of time, and a second phase of a clock is not required.

Slope compensation with adaptive slope

A switching converter and a method for providing an output voltage is presented. The switching converter includes an inductor coupled to a pair of power switches, a signal generator and a controller. The first power switch is used to magnetize the inductor, while the second power switch is used to de-magnetize it. The signal generator is adapted to generate a modulated signal having a pulse width variable between a minimum value and a maximum value and to drive the first and second power switches based on the modulated signal. Upon identifying that the modulated signal has the minimum pulse width value, the controller increases a reverse current flowing from the inductor through the second power switch to prevent the output voltage from increasing above a target value.

System and method for operating a switching converter in light load

A thermometer-coded Digital to Analog Converter (DAC) is described, whose output is changed with fast speed, and reduced output overshoot or undershoot. The thermometer-coded DAC has selection switches and an up/down counter, with DAC codes separated into higher and lower bits. The lower bits increase up to a maximum code, then decrease. The configuration of resistors in the DAC reduces output spike, especially at the DAC code changing point.

Thermometer digital to analog converter

A 'windowless' H-bridge buck-boost switching converter includes a regulation circuit with an error amplifier which produces a 'comp' signal, a comparison circuit which compares 'comp' with a &#x2018;ramp&#x2019; signal, and logic circuitry which receives the comparison circuit output and a mode control signal indicating whether the converter is to operate in buck mode or boost mode and operates the primary or secondary switching elements to produce the desired output voltage in buck or boost mode, respectively. A &#x2018;ramp&#x2019; signal generation circuit operates to shift the &#x2018;ramp&#x2019; signal up by a voltage Vslp(p&#x2212;p)+Vhys when transitioning from buck to boost mode, and to shift &#x2018;ramp&#x2019; back down by Vslp(p&#x2212;p)+Vhys when transitioning from boost to buck mode, thereby enabling the converter to operate in buck mode or boost mode only, with no need for an intermediate buck-boost region.

Windowless H-bridge buck-boost switching converter

An inductor current emulation circuit for use with a switching converter in which regulating the output voltage includes comparing an output which varies with the difference between the output voltage and a reference voltage with a 'ramp' signal which emulates the current in the output inductor. A current sensing circuit produces an output which varies with the current in the switching element that is turned on during the 'off' time, an emulated current generator circuit produces the &#x2018;ramp&#x2019; signal during both &#x2018;off&#x2019; and &#x2018;on&#x2019; times, a comparator circuit compares the &#x2018;ramp&#x2019; signal with at least one threshold voltage which varies with the sensed current and toggles an output when the &#x2018;ramp&#x2019; exceeds the thresholds, and a feedback circuit produces an output which adjusts the &#x2018;ramp&#x2019; signal each time the comparator circuit output toggles until the &#x2018;ramp&#x2019; signal no longer exceeds the threshold voltages.

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Yokohama, Japan

Hirohisa Tanabe