Abstract: A control circuit for a polarity inverting buck-boost DC-DC converter, includes an operational trans-conductance amplifier that has inputs to which a sensed voltage difference signal is applied and an output connected to an input of a voltage-to-duty-cycle converter. A compensation capacitance is connected between the output of the amplifier and a fixed supply terminal. The compensation capacitance includes a first capacitor that is permanently connected between the output of the amplifier and the fixed supply terminal and a second capacitor that has a switched connection between the output of the amplifier and the fixed supply terminal. The first capacitor has a small capacitance compared to the second capacitor. The switched connection of the second capacitor is controlled by a continuous-discontinuous mode detection circuit.

Abstract: A converter has a main feedback path and two auxiliary feedback paths from an output node to an auxiliary differential input pair of a comparator. The auxiliary feedback paths have different RC time constants so that a differential ramp signal is effectively applied to the auxiliary differential inputs of the comparator. The circuit design compensates for a negligibly small equivalent series resistor of an output capacitor so that modern capacitors may be used without compromising the stable oscillation of the converter.

Abstract: A DC-DC converter with an inductor connected in series with a power transistor between first and second terminals of a DC supply source, and with a modulator circuit that has a control output connected to a control gate of the power transistor. The modulator circuit provides a periodic pulse signal the duty cycle of which determines an output voltage at an output terminal of the converter. The modulator circuit comprises an oscillator that determines the frequency of the periodic pulse signal. The modulator circuit also comprises a feedforward structure that determines an approximated duty cycle for the pulse signal based on the value of the input voltage, the sensed output voltage and the amount of current flow in the inductor. An error amplifier in the modulator has a first input connected to a reference voltage source, a second input connected to the output terminal of the converter and an output that supplies a corrective signal used by the modulator to adjust the duty cycle of the pulse signal.

Abstract: A self-oscillating DC-DC buck converter with zero hysteresis is described. The converter comprises a comparator with a supply input, a non-inverting input to which a reference voltage is applied, an inverting input to which a feedback signal is applied, and an output to which a filter network is connected. The feedback signal is derived from the filter network and the output voltage of the converter is determined by the reference voltage. Connecting a filter network with an inductor and a capacitor to the output of the comparator and deriving the feedback signal from the filter network, results in an output of the comparator which is a DC output with a superimposed ripple. The level of the DC output is controlled by the reference voltage applied to the non-inverting input of the comparator, and the inductor current develops the ripple in the equivalent series resistance of the load circuit connected to the comparator output. The ripple can be regarded as the ramp signal in a conventional DC-DC converter.

Abstract: An integrated circuit including a precharge circuit for a DC/DC boost converter which includes a reference current circuit with a MOSFET transistor (MP4) that has a gate connected with the gate of the DC/DC boost converter's power MOSFET transistor (MP5) to form a current mirror. The precharge circuit works to approach the output voltage to the supply voltage prior to the converter startup. An included regulation circuit adjusts the gate potential at the power MOSFET transistor (MP5) and at the MOSFET transistor (MP4) in the reference circuit in response to a reduction of the drain-source voltage of the power MOSFET transistor (MP5) due to precharging load capacitance, in a sense to keep the precharge current through the power MOSFET transistor (MP5) constant.

Abstract: A switch mode power converter is provided which includes a switching cell with a supply input, an output and a control input. A summing comparator has first and second differential input pairs and an output. The output is connected to the control input of the switching cell. An oscillator provides a periodic waveform that is applied to a first one of the inputs of the first differential input pair of the summing comparator. An adjustable reference voltage source provides an adjustable reference voltage a predetermined fraction of which is applied to a second one of the inputs of the first differential input pair of the summing comparator. An error amplifier has differential outputs coupled to the second pair of differential inputs of the summing comparator and a differential input pair.

Abstract: A DC-DC converter with an inductor connected in series with a power transistor between first and second terminals of a DC supply source, and with a modulator circuit that has a control output connected to a control gate of the power transistor. The modulator circuit provides a periodic pulse signal the duty cycle of which determines an output voltage at an output terminal of the converter. The modulator circuit comprises an oscillator that determines the frequency of the periodic pulse signal. The modulator circuit also comprises a feedforward structure that determines an approximated duty cycle for the pulse signal based on the value of the input voltage, the sensed output voltage and the amount of current flow in the inductor. An error amplifier in the modulator has a first input connected to a reference voltage source, a second input connected to the output terminal of the converter and an output that supplies a corrective signal used by the modulator to adjust the duty cycle of the pulse signal.

Abstract: In the proposed method of generating a pulsed output signal from a periodic ramp signal and a reference voltage, the linear range of duty cycles of the pulsed output signal is significantly extended to minimum values. The ramp signal and the reference voltage are applied to inputs of a comparator and the output signal is taken from an output of the comparator. The ramp signal has a ramp that extends between a minimum voltage level and a maximum voltage level. The duty cycle of the pulse signal is controlled by varying the reference voltage between the minimum and maximum voltage levels. The ramp has an initial start section extending from the minimum voltage level and a main section extending between the initial section and the maximum voltage level. The ramp slope has a constant value over the main ramp section and a value greater than the constant value over the initial section.

Abstract: A DC/DC converter circuit including an inductance 10, two controllable switches 12, 14 and a controller 16 for controlling the switches 12, 14 is configured so that it is able to operate in two permanently alternating operating time phases. The switches 12, 14 in the DC/DC converter circuit are arranged so that when the controller 16 is in the first operating time phase it closes the first switch 12 and opens the second switch 14 in achieving a flow of energy from the input of the DC/DC converter circuit to the inductance 10 and then when the controller 16 is in the second operating time phase it opens the first switch 12 and closes the second switch 14 in achieving a flow of energy from the inductance 10 to the output of the DC/DC converter circuit. Prior to switching from one operating time phase into the other operating time phase an intermediate time phase is inserted for safety reasons, in which both switches 12, 14 of the DC/DC converter circuit are briefly opened.

Abstract: A control circuit for a polarity inverting buck-boost DC-DC converter, includes an operational trans-conductance amplifier that has inputs to which a sensed voltage difference signal is applied and an output connected to an input of a voltage-to-duty-cycle converter. A compensation capacitance is connected between the output of the amplifier and a fixed supply terminal. The compensation capacitance includes a first capacitor that is permanently connected between the output of the amplifier and the fixed supply terminal and a second capacitor that has a switched connection between the output of the amplifier and the fixed supply terminal. The first capacitor has a small capacitance compared to the second capacitor. The switched connection of the second capacitor is controlled by a continuous-discontinuous mode detection circuit.

Abstract: A voltage regulator includes a two-stage feedback circuit for driving a controller formed by a transistor 10. The feedback circuit includes an error amplifier 30 and an output amplifier 20, a simple compensating circuit in the form of a resistor RSZ inserted between the inverting input 22 and the non-inverting input 24 of the output amplifier 20 resulting in a high phase reserve of the feedback circuit. The resistor RSZ limits the gain of the error amplifier 30 for small load currents by reducing its effective output impedance. This compensating circuit results in the two-stage feedback circuit being highly stable even when very low load currents are involved. This now makes it possible to achieve a very simple linear voltage regulator architecture totally integrated on a single chip. It is especially in battery-powered handhelds such as e.g.

Abstract: In the proposed method of generating a pulsed output signal from a periodic ramp signal and a reference voltage, the linear range of duty cycles of the pulsed output signal is significantly extended to minimum values. The ramp signal and the reference voltage are applied to inputs of a comparator and the output signal is taken from an output of the comparator. The ramp signal has a ramp that extends between a minimum voltage level and a maximum voltage level. The duty cycle of the pulse signal is controlled by varying the reference voltage between the minimum and maximum voltage levels. The ramp has an initial start section extending from the minimum voltage level and a main section extending between the initial section and the maximum voltage level. The ramp slope has a constant value over the main ramp section and a value greater than the constant value over the initial section.

Abstract: A switch mode power converter is provided which includes a switching cell with a supply input, an output and a control input. A summing comparator has first and second differential input pairs and an output. The output is connected to the control input of the switching cell. An oscillator provides a periodic waveform that is applied to a first one of the inputs of the first differential input pair of the summing comparator. An adjustable reference voltage source provides an adjustable reference voltage a predetermined fraction of which is applied to a second one of the inputs of the first differential input pair of the summing comparator. An error amplifier has differential outputs coupled to the second pair of differential inputs of the summing comparator and a differential input pair.

Abstract: An integrated circuit including a precharge circuit for a DC/DC boost converter is disclosed with an inductor (L1), a power MOSFET transistor (MP5) connected in series with the inductor between a supply terminal and a load (Rload, Cload) that has a second end connected to ground. This precharge circuit further includes a reference current circuit with a MOSFET transistor (MP4) that has a gate connected with the gate of the power MOSFET transistor (MP5) to form a current mirror. The precharge circuit works to approach the output voltage to the supply voltage prior to the converter startup. An included regulation circuit adjusts the gate potential at the power MOSFET transistor (MP5) and at the MOSFET transistor (MP4) in the reference circuit in response to a reduction of the drain-source voltage of the power MOSFET transistor (MP5), in a sense to keep the precharge current through the power MOSFET transistor (MP5) constant.

Abstract: A DC/DC converter circuit including an inductance 10, two controllable switches 12, 14 and a controller 16 for controlling the switches 12, 14 is configured so that it is able to operate in two permanently alternating operating time phases. The switches 12, 14 in the DC/DC converter circuit are arranged so that when the controller 16 is in the first operating time phase it closes the first switch 12 and opens the second switch 14 in achieving a flow of energy from the input of the DC/DC converter circuit to the inductance 10 and then when the controller 16 is in the second operating time phase it opens the first switch 12 and closes the second switch 14 in achieving a flow of energy from the inductance 10 to the output of the DC/DC converter circuit. Prior to switching from one operating time phase into the other operating time phase an intermediate time phase is inserted for safety reasons, in which both switches 12, 14 of the DC/DC converter circuit are briefly opened.

Abstract: A voltage regulator includes a two-stage feedback circuit for driving a controller formed by a transistor 10. The feedback circuit includes an error amplifier 30 and an output amplifier 20, a simple compensating circuit in the form of a resistor RSZ inserted between the inverting input 22 and the non-inverting input 24 of the output amplifier 20 resulting in a high phase reserve of the feedback circuit. The resistor RSZ limits the gain of the error amplifier 30 for small load currents by reducing its effective output impedance. This compensating circuit results in the two-stage feedback circuit being highly stable even when very low load currents are involved. This now makes it possible to achieve a very simple linear voltage regulator architecture totally integrated on a single chip. It is especially in battery-powered handhelds such as e.g.

Abstract: The invention relates to a reference voltage source including a bipolar transistor having a base, a collector and an emitter electrode. The reference voltage source further comprises a Schottky diode (D) whose anode is connected to the base electrode of the bipolar transistor and whose cathode is connected to the collector electrode of the bipolar transistor. The currents flowing through the Schottky diode and bipolar transistor are each set so that a temperature-independent reference voltage (VREF) materializes at the collector electrode of the bipolar transistor.

Abstract: The invention relates to bandgap reference voltage generator circuit including a first bipolar transistor and a second bipolar transistor, a first resistor connected so that the voltage drop across it corresponds to the difference between the base/emitter voltages of the two bipolar transistors, and which is located in the collector current path of the second transistor, and a second resistor located in the collector current path of both transistors.

Abstract: The invention relates to a reference voltage source including a bipolar transistor having a base, a collector and an emitter electrode. The reference voltage source further comprises a Schottky diode (D) whose anode is connected to the base electrode of the bipolar transistor and whose cathode is connected to the collector electrode of the bipolar transistor. The currents flowing through the Schottky diode and bipolar transistor are each set so that a temperature-independent reference voltage (VREF) materializes at the collector electrode of the bipolar transistor.

Abstract: The invention relates to bandgap reference voltage generator circuit including a first bipolar transistor and a second bipolar transistor, a first resistor connected so that the voltage drop across it corresponds to the difference between the base/emitter voltages of the two bipolar transistors, and which is located in the collector current path of the second transistor, and a second resistor located in the collector current path of both transistors.