Abstract: A regulator circuit includes a first transistor coupled to a supply voltage and a second transistor coupled between the first transistor and an output node. The regulator circuit also includes a dynamic bias circuit that may selectively provide a bias voltage to a gate of the second transistor. During a first mode such as a low power mode, for example, the bias circuit may provide the bias voltage at a fixed percentage of the supply voltage as the supply voltage varies. In addition, during a second mode such as a high power mode, for example, the bias circuit may provide the bias voltage at a fixed offset from the supply voltage as the supply voltage varies.

Abstract: A technique includes energizing a storage element of a voltage regulator in response to the detection of an output voltage of the voltage regulator falling below a threshold level. The technique includes halting the energization of the storage element in response to the detection of a current in the storage element reaching a predetermined threshold.

Abstract: An inductor based DC-DC converter of the present invention employs two power switches such that only a fraction of inductor current flows through sensing circuitry. The sensing circuitry itself is comprised of sense transistors instead of resistors in order to further reduce power dissipation and temperature variations. The sensing circuitry includes a differential power supply that modifies a sense current employed as feedback to one of its inputs. The sense transistors are selected and configured such that the sense current is a relatively constant fraction of the inductor current of the converter.

Abstract: An undervoltage detection circuit includes a first transistor and a second transistor coupled to a supply voltage node and arranged to form a current mirror. The undervoltage detection circuit also includes a first bipolar transistor and a second bipolar transistor. A collector of the first bipolar transistor is coupled to the first transistor, and an emitter of the first bipolar transistor is coupled to a reference voltage node. A collector of the second bipolar transistor is coupled to the second transistor and an emitter of the second bipolar transistor is coupled to the reference voltage node through a first resistor. The undervoltage detection circuit further includes a third transistor coupled through a second resistor to an input voltage node. An output signal indicative of an input voltage is derived from a voltage established at the collector of the second bipolar transistor.

Abstract: Systems and methods for generating a reference voltage are disclosed. In one embodiment, an output voltage is generated that is the sum of a desirable reference voltage component and an undesirable voltage component. An additional voltage component that tends to be equal and opposite in sign to the undesirable voltage component is added to the output voltage, the additional voltage component thereby tending to cancel the undesirable voltage component.

Abstract: An inductor based DC-DC converter of the present invention employs two power switches such that only a fraction of inductor current flows through sensing circuitry. The sensing circuitry itself is comprised of sense transistors instead of resistors in order to further reduce power dissipation and temperature variations. The sensing circuitry includes a differential power supply that modifies a sense current employed as feedback to one of its inputs. The sense transistors are selected and configured such that the sense current is a relatively constant fraction of the inductor current of the converter.

Abstract: Disclosed are methods and circuits for providing a bandgap reference in an electronic circuit having a supply voltage and ground. The methods include steps for generating a bandgap reference current, mirroring the bandgap reference current, summing the mirrored currents, and modulating and outputting a bandgap reference voltage from the sum. Representative preferred embodiments are disclosed in which the methods of the invention are used in providing under-voltage protection and in providing a regulated output voltage. Circuits are disclosed for a bandgap reference voltage generator useful for providing a bandgap reference voltage in a circuit. A first current mirror for provides current from a supply voltage. A bandgap reference current circuit between the first current mirror and ground is configured for deriving a bandgap current proportional to absolute temperature. A second current mirror and control circuit are provided for summing the mirrored currents and modulating a bandgap reference voltage output.

Abstract: Disclosed are methods and circuits for providing a bandgap reference in an electronic circuit having a supply voltage and ground. The methods include steps for generating a bandgap reference current, mirroring the bandgap reference current, summing the mirrored currents, and modulating and outputting a bandgap reference voltage from the sum. Representative preferred embodiments are disclosed in which the methods of the invention are used in providing under-voltage protection and in providing a regulated output voltage. Circuits are disclosed for a bandgap reference voltage generator useful for providing a bandgap reference voltage in a circuit. A first current mirror for provides current from a supply voltage. A bandgap reference current circuit between the first current mirror and ground is configured for deriving a bandgap current proportional to absolute temperature. A second current mirror and control circuit are provided for summing the mirrored currents and modulating a bandgap reference voltage output.

Abstract: A embedded overcurrent protection circuit within the PWM feedback controller (30) of a power converter (100) having an novel current limit detection function that minimizes the effects of the turn-on period of the power device (14) is disclosed herein. This power converter includes a current limit detection circuit (10–20) that is reset on the rising edge of the system clock in a first step. In a second step, the power device (14) that is turned on. In another step, a current detecting circuit (10–20) detects the drain-to-source voltage across the power device (14) and the output current generated thereby. A sense circuit (18) compares the output current detected with a first predetermined limit value in another step. When the output current is less than the first predetermined limit value, a step is conducted where the output current is regulated by modulating the pulse width of the signal sent by a driver (12) to the control node of the power device (14).

Abstract: A embedded overcurrent protection circuit within the PWM feedback controller (30) of a power converter (100) having an novel current limit detection function that minimizes the effects of the turn-on period of the power device (14) is disclosed herein. This power converter includes a current limit detection circuit (10-20) that is reset on the rising edge of the system clock in a first step. In a second step, the power device (14) that is turned on. In another step, a current detecting circuit (10-20) detects the drain-to-source voltage across the power device (14) and the output current generated thereby. A sense circuit (18) compares the output current detected with a first predetermined limit value in another step. When the output current is less than the first predetermined limit value, a step is conducted where the output current is regulated by modulating the pulse width of the signal sent by a driver (12) to the control node of the power device (14).

Abstract: Disclosed are methods and circuits for providing a bandgap reference in an electronic circuit having a supply voltage and ground. The methods include steps for generating a bandgap reference current, mirroring the bandgap reference current, summing the mirrored currents, and modulating and outputting a bandgap reference voltage from the sum. Representative preferred embodiments are disclosed in which the methods of the invention are used in providing under-voltage protection and in providing a regulated output voltage. Circuits are disclosed for a bandgap reference voltage generator useful for providing a bandgap reference voltage in a circuit. A first current mirror for provides current from a supply voltage. A bandgap reference current circuit between the first current mirror and ground is configured for deriving a bandgap current proportional to absolute temperature. A second current mirror and control circuit are provided for summing the mirrored currents and modulating a bandgap reference voltage output.

Abstract: Disclosed are methods and circuits for providing a bandgap reference in an electronic circuit having a supply voltage and ground. The methods include steps for generating a bandgap reference current, mirroring the bandgap reference current, summing the mirrored currents, and modulating and outputting a bandgap reference voltage from the sum. Representative preferred embodiments are disclosed in which the methods of the invention are used in providing under-voltage protection and in providing a regulated output voltage. Circuits are disclosed for a bandgap reference voltage generator useful for providing a bandgap reference voltage in a circuit. A first current mirror for provides current from a supply voltage. A bandgap reference current circuit between the first current mirror and ground is configured for deriving a bandgap current proportional to absolute temperature. A second current mirror and control circuit are provided for summing the mirrored currents and modulating a bandgap reference voltage output.

Abstract: A voltage detection circuit utilizes a comparator to compare first and second input voltages to generate a control signal when the difference between the first and second input voltages exceeds a threshold. The threshold voltage is generated by injecting a known current into a resistance in series with one of the inputs. The voltage detection circuit utilizes a first level of injected current when the input differential voltage differs from the threshold by a predetermined voltage level. The injected current rises to a second level as the second input voltage approaches the first input voltage in order to obtain a more accurate voltage comparison.

Abstract: A output driver architecture (100) is proposed that uses thin gate-oxide core and thin gate-oxide Drain-extended transistors that can directly interface with voltage supplies up to six times the normal rating of the transistor. A bias generator (101), level shifter (103) and output stage (105) are adapted to buffer an input signal with a voltage swing of less than the normal operating voltage of the transistors to an output signal with a voltage swing of up to approximately six times the normal operating voltage of the transistors. The bias generator is interfaced directly with a high voltage power supply and generates a bias voltage with a magnitude of less than the dielectric breakdown of the transistors internal to the level shifter and output stage.

Abstract: A voltage detection circuit utilizes a comparator to compare first and second input voltages to generate a control signal when the difference between the first and second input voltages exceeds a threshold. The threshold voltage is generated by injecting a known current into a resistance in series with one of the inputs. The voltage detection circuit utilizes a first level of injected current when the input differential voltage differs from the threshold by a predetermined voltage level. The injected current rises to a second level as the second input voltage approaches the first input voltage in order to obtain a more accurate voltage comparison.

Abstract: An output stage provides increased current sourcing capability through a technique of local positive feedback. Current through a transistor MP2 is mirrored by the output current source IOUT that is desired to be increased. Without positive feedback, the gate of MN2 would be fixed by MP1 and MN1, and when input voltage VIN decreases by an incremental voltage &Dgr;V, the resulting current increase would distribute an increased voltage not only across MP2's VGS but also in the VGS of another transistor MN2; therefore, undesirably, not all of the &Dgr;V voltage change is mirrored in IOUT. However, if positive feedback such as MP5 is provided, the feedback dynamically increases the voltage at the gate of MN2. The increased voltage of MN2's gate essentially provides more voltage “headroom” for MP2 and MN2, and allows current through MP2 to increase with any voltage decrease in VIN.

Abstract: An output stage provides increased current sourcing capability through a technique of local positive feedback. Current through a transistor MP2 is mirrored by the output current source IOUT that is desired to be increased. Without positive feedback, the gate of MN2 would be fixed by MP1 and MN1, and when input voltage VIN decreases by an incremental voltage &Dgr;V, the resulting current increase would distribute an increased voltage not only across MP2's VGS but also in the VGS of another transistor MN2; therefore, undesirably, not all of the &Dgr;V voltage change is mirrored in IOUT. However, if positive feedback such as MP5 is provided, the feedback dynamically increases the voltage at the gate of MN2. The increased voltage of MN2's gate essentially provides more voltage “headroom” for MP2 and MN2, and allows current through MP2 to increase with any voltage decrease in VIN.

Abstract: An LDO regulator automatically switches from the SLEEP mode to the ON mode without the need for an externally generated control signal. The LDO regulator utilizes a pair of drive amplifiers to drive a SLEEP mode pass transistor and a normal ON mode pass transistor, respectively. The regulator also has a circuit for adjusting the bias applied to the amplifiers for each mode of operation.

Abstract: The present invention provides a low drop-out voltage regulator (200) that reduces gate capacitance and simplifies the compensation needed to maintain stability, without requiring additional and/or larger Miller capacitors (108), by splitting the output (220, 221) of the driver (112A) for different operational modes, selectively driving a small power device (206), a large power device (214) or both based on the mode.

Abstract: The buffer circuit using a transconductance amplifier has a unity-gain feedback configured amplifier which includes: a first transistor M3; a second transistor M4 mirroring a current in the first transistor M3, the second transistor M4 is sized larger than the first transistor M3; a third transistor M1 coupled :o the first transistor; a fourth transistor M2 coupled to the second transistor M1, the fourth transistor M2 is sized larger than the third transistor M1; and a tail current source MS coupled to the third and fourth transistors M1 and M2. The second and fourth transistors M4 and M2 are sized larger than the first and third transistors M3 and M1 to form a transconductance multiplier. This reduces output impedance without increasing bias current.