Abstract: A cascode power switch for use in a MESFET based switching regulator includes a MOSFET in series with a normally-off MESFET. The cascode power switch is typically connected in between a power source and a node Vx. The node Vx is connected to an output node via an inductor and to ground via a Schottky diode or a second MESFET or both. A control circuit drives the MESFET (and the second MESFET) so that the inductor is alternately connected to the battery and to ground. The MOSFET is switched off during sleep or standby modes to minimize leakage current through the MESFET. The MOSFET is therefore switched at a low frequency compared to the MESFET and does not contribute significantly to switching losses in the converter.

Abstract: A reverse current comparator for use in switching regulators includes a differential stage configured to encode the difference in voltage between an N and a P input. The differential stage feeds one or more gain stages. At least one of the gain stages includes one or more hysteresis devices. When the voltage of the N input exceeds the voltage of the P input by a predetermined margin, the hysteresis device causes the regulator to enter a triggered state in which it outputs a non-zero output voltage. Subsequent changes to the N and P inputs do not change the regulator output until a RESET input is asserted and which point the regulator enters a reset state and is ready to be triggered.

Abstract: Various integrated circuit devices, including a lateral DMOS transistor, a quasi-vertical DMOS transistor, a junction field-effect transistor (JFET), a depletion-mode MOSFET, and a diode, are formed inside an isolation structure which includes a floor isolation region and a trench extending from the surface of the substrate to the floor isolation region. The trench may be filled with a dielectric material or may have a conductive material in a central portion with a dielectric layer lining the walls of the trench. Various techniques for terminating the isolation structure by extending the floor isolation region beyond the trench, using a guard ring, and a forming a drift region are described.

Abstract: Various integrated circuit devices, in particular a transistor, are formed inside an isolation structure which includes a floor isolation region and a trench extending from the surface of the substrate to the floor isolation region. The trench may be filled with a dielectric material or may have a conductive material in a central portion with a dielectric layer lining the walls of the trench. Various techniques for terminating the isolation structure by extending the floor isolation region beyond the trench, using a guard ring, and a forming a drift region are described.

Abstract: A Buck converter that includes a cascode switch comprising a series connected MESFET and MOSFET power switch. The cascode power switch is typically connected in between a power source and a node Vx. The node Vx is connected to an output node via an inductor and to ground via a Schottky diode or a second MESFET or both. A control circuit drives the MESFET (and the second MESFET) so that the inductor is alternately connected to the battery and to ground. The MOSFET is switched off during sleep or standby modes to minimize leakage current through the MESFET. The MOSFET is therefore switched at a low frequency compared to the MESFET and does not contribute significantly to switching losses in the converter.

Abstract: A MESFET based boost converter includes an N-channel MESFET connected to a node Vx. An inductor connects the node Vx to a battery or other power source. The node Vx is also connected to an output node via a Schottky diode or a second MESFET or both. A control circuit drives the MESFET (and the second MESFET) so that the inductor is alternately connected to ground and to the output node. The maximum voltage impressed across the low side MESFET is optionally clamped by a Zener diode. In some implementations, the MESFET is connected in series with a MOSFET. The MOSFET is switched off during sleep or standby modes to minimize leakage current through the MESFET. The MOSFET is therefore switched at a low frequency compared to the MESFET and does not contribute significantly to switching losses in the converter. In other implementations, more than one MESFET is connected in series with a MOSFET, the MOSFETs being switched off during periods of inactivity to suppress leakage currents.

Abstract: A DC/DC converter includes a pre-regulator stage, which may include a Buck converter, and a post-converter stage, which may include a charge pump. The duty factor of the pre-regulator stage is controlled by a feedback path that extends from the output terminal of the pre-regulator stage or the post-converter stage. The pre-regulator steps the input DC voltage down by a variable amount depending on the duty factor, and the post-converter steps the voltage at the output of the pre-regulator up or down by an positive or negative integral or fractional value. The converter overcomes the problems of noise glitches, poor regulation, and instability, even near unity input-to-output voltage conversion ratios.

Abstract: A DC/DC converter includes a pre-converter stage, which may include a charge pump, and a post-regulator stage, which may include a boost converter. The duty factor of the post-regulator stage is controlled by a feedback path that extends from the output terminal of the DC/DC converter to an input terminal in the post-regulator stage. The pre-converter steps the input DC voltage up or down by a positive or negative integral or fractional value, and the post-regulator steps the voltage up by a variable amount depending on the duty factor at which the post-regulator is driven. The converter overcomes the problems of noise glitches, poor regulation, and instability, even near unity input-to-output voltage conversion ratios.

Abstract: A DC/DC converter includes a pre-regulator stage, which may include a boost converter, and a post-converter stage, which may include a charge pump. The duty factor of the pre-regulator stage is controlled by a feedback path that extends from the output terminal of the pre-regulator stage or the post-converter stage. The pre-regulator steps the input DC voltage up by a variable amount depending on the duty factor, and the post-converter steps the voltage at the output of the pre-regulator up or down by an positive or negative integral or fractional value. The converter overcomes the problems of noise glitches, poor regulation, and instability, even near unity input-to-output voltage conversion ratios.

Abstract: A family of semiconductor devices is formed in a substrate that contains no epitaxial layer. In one embodiment the family includes a 5V CMOS pair, a 12V CMOS pair, a 5V NPN, a 5V PNP, several forms of a lateral trench MOSFET, and a 30V lateral N-channel DMOS. Each of the devices is extremely compact, both laterally and vertically, and can be fully isolated from all other devices in the substrate.

Abstract: A family of semiconductor devices is formed in a substrate that contains no epitaxial layer. In one embodiment the family includes a 5V CMOS pair, a 12V CMOS pair, a 5V NPN, a 5V PNP, several forms of a lateral trench MOSFET, and a 30V lateral N-channel DMOS. Each of the devices is extremely compact, both laterally and vertically, and can be fully isolated from all other devices in the substrate.

Abstract: A battery charger apparatus for charging a battery, comprises a charge-current control circuit for receiving a charge-current control signal to control an amount of charge current being drawn from an input source, e.g.

Abstract: Mobile devices have limited power sources. In some cases, such as camera flash operations in cell phones or digital cameras, the power required to provide bright illumination is significant and exceeding the battery voltage level. In order to supply burst power or continuous high power to light sources, such as white LEDs (light emitting diodes), mobile devices typically employ charge storage functioning as energy reservoir that can supply the required power. One such charge storage is a supercapacitor that can supply the needed power repeatedly by discharging and recharging. Various embodiments of the present invention include devices and methods for providing the charge energy and controlling the charge and discharge operations.

Abstract: Charge storage devices (e.g., batteries or supercapacitors) need to be charged from time to time. In an apparatus, to protect a charge storage device as well as the supply used to charge it, the apparatus typically includes power loop control circuitry. One approach to implementing the power loop control employs a temperature sensor in combination with soft start circuitry in order to protect the circuitry from a rapidly increasing temperature when charge current increases. The soft start circuitry allows for controlled step-wise increase and regulation of the current. The approach preferably allows for selecting the number and resolution of such incremental steps. Various embodiments of the invention include devices and methods for controlling power and may take into account temperature in step-wise regulation of the charge current.

Abstract: Devices, such as mobile devices, may be exposed, to short circuit and output overload events. To protect against such events, mobile devices typically include current limit circuits. Some current limit circuits may involve user programmable function. User programmable function may need accurate current limit detectors. One approach to improving resolution and accuracy of current limit detectors using a single resistive device is to magnify the operating current range. Various embodiments of the present invention include devices and methods for detecting pre-programmed current limits.

Abstract: Devices, such as mobile devices, may be exposed to short circuit and output overload events. To protect against such events, mobile devices typically include circuitry to limit currents so as not to exceed a pre-programmed current limit. Various embodiments of the present invention include devices and methods for detecting pre-programmed current limits and for limiting currents in response to such detection. In some embodiments, both the current limit detector and the current limit controller circuitry include scaled current switches. The scaling may be substantially similar between the programmed-current limit detector and the current limit controller circuitry.

Abstract: Devices, such as mobile devices, may be exposed to short circuit and output overload events. To protect against such events, mobile devices typically include current limit circuits. Some current limit circuits may involve user programmable function. User programmable function may need accurate current limit detectors. Various embodiments of the present invention include devices and methods for detecting one or more programmed current limits. Some embodiments allow for a user application to select among parallel or serial configurations of current detection circuitry. Each such configuration may include multiple resistive devices of different resistive values.

Abstract: The synchronous rectifier MOSFET in a Buck or boost DC/DC converter is operated as a current source rather than being turned off, thereby reducing undesirable losses in efficiency, the generation of unwanted electrical and radiated noise, and numerous other potential problems, particularly when the converter is operating in a light-load condition.

Abstract: All low-temperature processes are used to fabricate a variety of semiconductor devices in a substrate the does not include an epitaxial layer. The devices include a non-isolated lateral DMOS, a non-isolated extended drain or drifted MOS device, a lateral trench DMOS, an isolated lateral DMOS, JFET and depletion-mode devices, and P-N diode clamps and rectifiers and junction terminations. Since the processes eliminate the need for high temperature processing and employ “as-implanted” dopant profiles, they constitute a modular architecture which allows devices to be added or omitted to the IC without the necessity of altering the processes used to produce the remaining devices.

Abstract: A rectifier MESFET includes an N-channel MESFET having its gate connected to its source, and at the same current density having a voltage drop lower than the gate Schottky diode. A Schottky diode may be connected in parallel with the N-channel device to provide over current protection. A Zener may also be connected in parallel to provide reverse voltage protection. A second N-channel device may be connected in parallel. The addition of the second N-channel provides two different operational mode: synchronous rectification where the majority of current flows through the low resistance first N-channel device and asynchronous rectification where the majority of current flows through the somewhat higher resistance first N-channel device.