Patent•
DC to DC converter with high efficiency for light loads
12 Feb 1997-
TL;DR: In this article, a DC-to-DC converter which maintains high efficiency over broad current ranges in a current mode switching regulator circuit without changing operational mode is presented, where a low ripple voltage is maintained over the entire load range and good voltage regulation is maintained with high efficiency.
Abstract: A DC to DC converter which maintains high efficiency over broad current ranges in a current mode switching regulator circuit without changing operational mode. A low ripple voltage is maintained over the entire load range and good voltage regulation is maintained with high efficiency. This is possible because the switching frequency is adjusted in accordance with the load without changing operational states, thus making it unnecessary to define plural states of operation. The timing of turning on the switch(es) varies since the switch(es) is (are) turned on when two set (ready) signals both become ready. For fixed frequency switching applications, switching pulses from a fixed frequency oscillator as a first set signal are skipped when a second set signal is not ready. On the other hand, for a variable frequency switching scheme which is implemented by driving the switching with a one-shot having a constant OFF time, the switching pulse is created after both set signals become active. A low pass filter is also used to dynamically adjust the minimum peak inductor current and to minimize ripple voltage for low load conditions so that a smaller output capacitor may be used.
Citations
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Patent•
02 Sep 2009TL;DR: In this paper, a wireless power transceiver and device comprising an antenna including a parallel resonator configured to resonate in response to a substantially unmodulated carrier frequency is described. But the authors do not specify a power conversion circuit.
Abstract: Exemplary embodiments are directed to wireless power transfer. A wireless power transceiver and device comprise an antenna including a parallel resonator configured to resonate in response to a substantially unmodulated carrier frequency. The wireless power transceiver further comprises a bidirectional power conversion circuit coupled to the parallel resonator. The bidirectional power conversion circuit is reconfigurable to rectify an induced current received at the antenna into DC power and to induce resonance at the antenna in response to DC power.
381 citations
Patent•
16 Sep 2009TL;DR: In this paper, a wireless power transmitter includes a transmit antenna configured as a resonant tank including a loop inductor and an antenna capacitance, and an amplifier configured to drive the transmit antenna and a matching circuit operably coupled between the transmitter and the amplifier.
Abstract: Exemplary embodiments are directed to wireless power transfer. A wireless power transmitter includes a transmit antenna configured as a resonant tank including a loop inductor and an antenna capacitance. The transmitter further includes an amplifier configured to drive the transmit antenna and a matching circuit operably coupled between the transmit antenna and the amplifier. The transmitter also includes a capacitor integrating the antenna capacitance and a matching circuit capacitance.
226 citations
Patent•
25 Apr 2000TL;DR: In this article, a voltage regulator is employed 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.
Abstract: 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.
203 citations
Patent•
21 Jan 2004
TL;DR: In this article, a multiple bi-directional input/output power control system includes a network of functional blocks housed in a single enclosure, providing DC power to one or more DC loads, and providing control and internal pathways.
Abstract: A multiple bi-directional input/output power control system includes a network of functional blocks housed in a single enclosure, providing DC power to one or more DC loads, and providing control and internal pathways, sharing one or more AC and/or DC power inputs. The system feeds back AC power from the DC power source into an AC input connection, and the fed-back AC power is shared by other AC loads. The system operates at least one alternative source of DC in a dynamic manner, allowing maximization of power generating capability at respective specific operating conditions of the moment. Power isolation may be handled by an AC isolation block right at a power input. Therefore all other blocks within a multi-function power control unit (MFPCU) are isolated from AC ground.
171 citations
Patent•
26 Oct 2000
TL;DR: In this paper, a power supply controller for switched mode power supply includes a drain terminal, source terminal, a control terminal and a multi-function terminal, which can provide any one or some of a plurality of functions including on/off control, external current limit adjustments, under-voltage detection, overvoltages detection and maximum duty cycle adjustment.
Abstract: A power supply controller having a multi-function terminal. In one embodiment, a power supply controller for switched mode power supply includes a drain terminal, a source terminal, a control terminal and a multi-function terminal. The multi-function terminal may be configured in a plurality of ways providing any one or some of a plurality of functions including on/off control, external current limit adjustments, under-voltage detection, over-voltage detection and maximum duty cycle adjustment. The operation of the multi-function terminal varies depending on whether a positive or negative current flows through the multi-function terminal. A short-circuit to ground from the multi-function terminal enables the power supply controller. A short-circuit to a supply voltage from the multi-function terminal disables the power supply controller. The current limit of an internal power switch of the power supply controller may be adjusted by externally setting a negative current from the multi-function terminal. The multi-function terminal may also be coupled to the input DC line voltage of the power supply through a resistance to detect an under-voltage condition, an over-voltage condition and/or adjust the maximum duty cycle of power supply controller. Synchronization of the oscillator of the power supply controller may also be realized by switching the multi-function terminal to power or ground at the desired times.
159 citations
References
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TL;DR: The new Art of Electronics retains the feeling of informality and easy access that helped make the earlier editions so successful and popular, and is an indispensable reference and the gold standard for anyone, student or researcher, professional or amateur, who works with electronic circuits.
1,764 citations
Patent•
22 Mar 1994TL;DR: In this paper, a circuit and method for controlling a switching voltage regulator having a switch including one or more switching transistors and an output adapted to supply current at a regulated voltage to a load including an output capacitor is presented.
Abstract: A circuit and method for controlling a switching voltage regulator having (1) a switch including one or more switching transistors and (2) an output adapted to supply current at a regulated voltage to a load including an output capacitor. The circuit and method generates a control signal to turn said one or more switching transistors OFF under operating conditions when the voltage at the output is capable of being maintained substantially at the regulated voltage by the charge on the output capacitor. Such a circuit and method increases the efficiency of the regulator circuit particularly at low average current levels.
672 citations
TL;DR: In this paper, a low-power breadboard operating at 200-300 kHz has been built for switching power supplies and battery chargers, which can operate in either the step-up or step-down mode.
Abstract: Transistor dc-dc converters which employ a resonant circuit are described. A resonant circuit is driven with square waves of current or voltage, and by adjusting the frequency around the resonant point, the voltage on the resonant components can be adjusted to any practical voltage level. By rectifying the voltage across the resonant elements, a dc voltage is obtained which can be either higher or lower than the input dc voltage to the converter. Thus, the converter can operate in either the step-up or step-down mode. In addition, the switching losses in the inverter devices and rectifiers are extremely low due to the sine waves that occur from the use of a resonant circuit (as opposed to square waves in a conventional converter); also, easier EMI filtering should result. In the voltage input version, the converter is able to use the parasitic diode associated with an FET or monolithic Darlington, while in the current input version, the converter needs the inverse blocking capability which can be obtained with an IGT or GTO device. A low-power breadboard operating at 200-300 kHz has been built. Two typical application areas are switching power supplies and battery chargers. The converter circuits offer improvements over conventional circuits due to their high efficiency (low switching losses), small reactive components (high-frequency operation), and their step-up/stepdown ability.
371 citations
Patent•
IBM1
TL;DR: In this paper, the value of the inductor is chosen with respect to the input and output voltages and frequencies of operation involved, to insure that the current polarity reverses each cycle, raising the node voltage to the level of the input voltage.
Abstract: A DC to DC power converter having reduced switching loss for operation at high frequencies. As disclosed, a buck, or forward, converter includes a first FET as the switching device in series with an inductor and a second FET as the flywheel device. At the common node to which the two FET's and the inductor are connected, there is sufficient capacitance that the FET's may be turned off without appreciable voltage change across the FET's. The value of the inductor is chosen, with respect to the input and output voltages and frequencies of operation involved, to insure that the inductor current polarity reverses each cycle, raising the node voltage to the level of the input voltage, substantially eliminating turn-on losses of the first FET. Control circuitry is provided for regulation of the power converter to control the peak-to-peak current in the inductor and to insure that at least a selected minimum value of the inductor current is present for each cycle of operation of the converter. An over-voltage protection circuit for the output of the converter is also provided.
288 citations
Patent•
05 Sep 1995
TL;DR: In this paper, a switching voltage regulator achieves high efficiency by automatically switching between a PFM mode and a PWM mode by monitoring the output voltage and the output current, wherein the regulator operates in PFM at small output currents and in PWM at moderate to large output currents.
Abstract: A switching voltage regulator achieves high efficiency by automatically switching between a pulse frequency modulation (PFM) mode and a pulse-width modulation (PWM) mode. Switching between the modes of voltage regulation is accomplished by monitoring the output voltage and the output current, wherein the regulator operates in PFM mode at small output currents and in PWM mode at moderate to large output currents. PFM mode maintains a constant output voltage by forcing the switching device to skip cycles when the output voltage exceeds its nominal value. In PWM mode, a PWM signal having a variable duty cycle controls the switching device. A constant output voltage is maintained by feedback circuitry which alters the duty cycle of the PWM signal according to fluctuations in the output voltage.
208 citations