Micrel, Incorporated

Micro Linear Corporation

Micrel, Incorporation

Charles Vinn

Matthew Weng

David J Kunst

Raymond David Zinn

Ioan Stoichita

Shekar Mallikarjunaswamy

Martin J Alter

Gwilym Francis Luff

Carlos A Laber

Paolo Nora

Ramesh Selvaraj

Bruce C Larson

Daniel J DeBeer

Wendy Ng

A switching regulator using current mode control and adaptive slope compensation includes a DC correction circuit to introduce a DC correction signal to cancel the DC offset error generated by the slope compensation signal. In some embodiments, the DC correction signal is a function of the input voltage and the output voltage and is applied in response to the slope compensation signal being applied. In one embodiment, the DC correction signal is a linear function of the input voltage and the output voltage.

Switching regulator using adaptive slope compensation with DC correction

A driver circuit for controlling a high-side power switch of a switching regulator includes: a logic circuit configured to generate a gate control signal for turning on the power switch; a diode having coupled to a first power supply voltage; a capacitor having a first electrode coupled to the cathode of the diode and a second electrode coupled to the switching output voltage; and a delay circuit configured to receive the gate control signal and to generate a delayed gate control signal. In operation, the capacitor is precharged to about the first power supply voltage. When the power switch is turned on, a first output drive transistor is turned on to distribute the charge stored on the capacitor to the gate terminal of the high-side power switch, and after the predetermined delay, a second output drive transistor is turned on to drive the output node to a high supply voltage.

Switching regulator with optimized switch node rise time

A voltage regulation system is provided including detecting a feedback voltage less than a reference voltage; asserting a current source gate output by the feedback voltage less than the reference voltage; activating a gated current source by the current source gate output; and waiting a delay interval before negating the current source gate output for turning off the gated current source.

Voltage regulation system

A method for providing adaptive compensation for an electrical circuit where the electrical circuit includes an inductor-capacitor network connected in a feedback loop being compensated by a first compensation capacitance value and a second compensation capacitance value defining the frequency locations of two compensation zeros includes: measuring the inductance value of the inductor; when the inductance value is greater than a first threshold value, increasing the first and second compensation capacitance values so that the frequency locations of the two compensation zeros are adjusted for compensating the poles introduced by the first inductor and the first capacitor; and when the inductance value is less than the first threshold value, decreasing the first and second compensation capacitance values so that the frequency locations of the two compensation zeros are adjusted for compensating the poles introduced by the first inductor and the first capacitor.

Adaptive compensation scheme for LC circuits in feedback loops

An integrated circuit system is provided including forming a differential pair; reducing a mismatch in the differential pair by: coupling an amplifier to the differential pair; and coupling a local feedback network to the amplifier in which referencing the local feedback network includes coupling a first voltage; and driving an output transistor by the amplifier.

Integrated circuit system for line regulation of an amplifier

A voltage regulator is disclosed having a switching regulator portion and an LDO regulator portion on a single chip. The switching portion switches one or more transistors at a high frequency to supply a voltage to a terminal of a series transistor of an LDO regulator. A second terminal of the series transistor provides the output voltage of the LDO regulator. The LDO regulator controls the conductivity of the series transistor to regulate the LDO regulator output voltage to be a desired fixed value. To minimize power dissipation in the series transistor, a feedback signal is taken from the series transistor indicating the level of saturation of the series transistor. This feedback signal is used by the switching regulator to adjust the switching regulator's output voltage such that the voltage supplied to the series transistor is close to the output voltage of the LDO. If there is a change of current, temperature, or process variations, the switching regulator voltage will be adjusted accordingly to keep the series transistor at a desired level in saturation. By minimizing the voltage drop across the series transistor and operating the series transistor at an optimum level of saturation, the overall regulator is highly efficient.

LDO with slaved switching regulator using feedback for maintaining the LDO transistor at a predetermined conduction level

A buck switching regulator formed on an integrated circuit receives an input voltage and provides a switching output voltage on a switch output node using a constant on-time, variable off-time feedback control loop. The buck switching regulator includes an amplifier comparing a feedback voltage to a reference voltage and generating an output voltage on an output terminal, a first capacitor and a first resistor connected in series between the switch output node and the output terminal of the amplifier, and a second capacitor coupled between the DC output voltage node and the output terminal of the amplifier. The first capacitor and the first resistor generate a ripple voltage signal which is injected onto the output terminal of the amplifier for use in the constant on-time, variable off-time feedback control scheme. The magnitude of the ripple voltage signal is a function of the capacitance value of the second capacitor.

Constant on-time regulator with internal ripple generation and improved output voltage accuracy

One embodiment of the invention is a hybrid boost regulator that includes a conventional boost regulator chip that operates when its input voltage is above 2.5 volts and a pre-boost circuit that operates when its input voltage is above 1 volt. A single 1.5 volt battery may be used to power the hybrid boost regulator. The pre-boost circuit is connected to the voltage input terminal of the boost regulator chip. The pre-boost circuit boosts the battery voltage (e.g., 1.5v) at an output terminal of the hybrid boost regulator to approximately the minimum operating voltage (e.g., 2.5v) of the boost regulator chip. Since this pre-boosted voltage is applied to the voltage input terminal of the boost regulator chip, the boost regulator chip will become operational when the ramping output voltage of the hybrid boost regulator exceeds about 2.5 volts. Once the boost regulator chip is operational, the pre-boost circuit is then turned off, and the boost regulator chip runs off the 1.5 volt power supply to ramp up the output voltage to the full regulated voltage.

Extending the voltage operating range of boost regulators

Describe is a device for a multiplexing, output current-sensed, boost converter circuit which may be used as an LED driver. A boost converter LED driver circuit using a single set of passive external LC components for controlling the current through, and thus the output of, one and more than one bank of LEDs. The present invention allows for regulated current in one and more than one bank of LEDs by sensing current in the controller. The output voltage of a switcher adjusts it's level automatically until the current to the LEDs is set to the desired LED threshold requirement.

Light emitting diode driver circuit

For load currents greater than a threshold current, the voltage regulator operates in a conventional manner by fully turning on and off one or more switching transistors at a duty cycle necessary to maintain the output voltage a regulated voltage. Upon a load current below a threshold being detected, a controller stops the switching of the transistor(s) and applies a reduced drive signal to the high side transistor so as to apply a constant trickle current to the load. Unnecessary components are shut down to save power. When the output voltage falls below a threshold, the normal switching routine is resumed to recharge the regulator's output capacitor to a certain level, and the regulator once again enters the light load current mode. By not completely shutting down the transistors at light load currents, as in done in a conventional intermittent-operation mode, there is lower power loss by less frequent switching of the transistor(s).

Switching voltage regulator with low current trickle mode

A PFM-type voltage regulator circuit converts an unregulated input voltage into a regulated output voltage using a first transistor controlled by a pulse control circuit and a second transistor controlled by a linear regulator circuit. The linear regulator circuit controls the second transistor when the regulated output voltage falls to a predetermined minimum target voltage level, thereby maintaining the regulated output voltage at the minimum target voltage level. The pulse control circuit detects the current passing through the second transistor, and in response generates a pulse signal having a predetermined duration that fully turns on the first transistor. The voltage through the first transistor is converted to an increasing inductor current that refreshes the regulated output voltage to a maximum target voltage level. When the pulse signal ends, the regulated output voltage again begins to fall toward the predetermined minimum target voltage level, and the cycle is repeated.

Pulse frequency modulated voltage regulator with linear regulator control

A comparator circuit having improved operational characteristics. A predetermined voltage drop device is provided, such as an exemplary embodiment Schottky diode, having an anode connected to circuit power supply voltage and an output stage of the comparator and a cathode connected to an input stage of the comparator. The predetermined voltage drop device effects a lowering of the power supply voltage for the output stage bias between said power supply voltage and said common voltage. This reduces the required swing of the output stage drivers during a comparator input signal transition and reduces propagation delay of said comparator.

Propagation delay characteristic comparator circuit

A transistor is formed with a source ballast resistor that regulates channel current. In an LDMOS transistor embodiment, the source ballast resistance may be formed using a high sheet resistance diffusion self aligned to the polysilicon gate, and/or by extending a depletion implant from under the polysilicon gate toward the source region. The teachings herein may be used to form effective ballast resistors for source and/or drain regions, and may be used in many types of transistors, including lateral and vertical transistors operating in a depletion or an enhancement mode, and BJT devices.

Ballast resistors for transistor devices

The present invention provides an apparatus and method for improving the accuracy of circuits. The apparatus includes a replicate circuit and a trim determination circuit. The trim determination circuit includes a measurable circuit element and determines the state of the measurable element. The replicate circuit includes a replicate circuit element which has similar electrical characteristics as the measurable element, and is configured to aid in determining an adjustable test current. The trim determination circuit generates a test current which is proportional to the adjustable test current. The test current is passed through the measurable element such that a first voltage drop occurs across the measurable element. A measured current is generated at a current level dictated by the voltage drop across the measurable element, such that the state of the measurable element is determined by the difference between the measured current and a scaled reference current.

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Milpitas, CA, United States of America

Charles Vinn