Patent application number | Description | Published |
20080218223 | POWER ON DETECTION CIRCUIT - A power on detection circuit for accurately detecting an input voltage with a simple circuit structure and reduced current consumption includes a voltage conversion circuit, which converts input voltage into current, and a latch circuit, which holds the power on detection signal. The voltage conversion circuit supplies output current to a current source and a capacitor via a connection node. The current source generates a flow of current that is proportional to the absolute temperature. When the output current of the voltage conversion circuit becomes greater than the current of the current source, the capacitor is charged and the voltage at the connection node is pulled up. A latching circuit is activated in accordance with the voltage at the connection node to output a power on detection signal. | 09-11-2008 |
20080258696 | SERIES REGULATOR CIRCUIT - A series regulator circuit for reducing current consumption, enabling switching between different current consumption modes, and suppressing output voltage fluctuations. A constant current source | 10-23-2008 |
20090153249 | RAIL TO RAIL BUFFER AMPLIFIER - A buffer amplifier having a wide output voltage range includes a first source follower circuit having a first current source and a first transistor, and a second source follower circuit having a second current source and a second transistor. The first source follower circuit has an output terminal connected to a gate of a third transistor and a source of a fourth transistor. The second source follower circuit has an output terminal connected to a gate of a fifth transistor and a source of a sixth transistor. First and second voltages are respectively supplied to the gates of the fourth and sixth transistors. The sixth transistor is operated in place of the fifth transistor in a low voltage range, and the fourth transistor is operated in place of the third transistor in a high voltage range. | 06-18-2009 |
20090273323 | SERIES REGULATOR WITH OVER CURRENT PROTECTION CIRCUIT - A series regulator with an over current protection circuit regulates output current at an output terminal by controlling an output transistor. There is a current sense transistor with a conductivity that is dependent on the conductivity of the output transistor. A current limiting transistor is connected between an input power supply terminal and a differential amplifier output that controls the conductivity of the output transistor. A current supply source provides current to a constant current source and a converter output of a current to voltage converter. The converter output is connected to a control electrode of the current limiting transistor. A first differential transistor couples the current sense transistor to the constant current source and a second differential transistor couples the current supply source to the constant current source. In operation, the current sense transistor controls the conductivity of the second differential transistor thereby varying a control current supplied from the current supply source to the constant current source. When the control current matches a limiting threshold value, a voltage control signal at the converter output controls the current limiting transistor to thereby limit maximum current flow through the output transistor. | 11-05-2009 |
20100097047 | SERIES REGULATOR CIRCUIT - A low drop out series regulator circuit for generating an output voltage that does not rely on voltage feedback or require a capacitor for stable operation includes first and second current sources connected in series between a supply voltage and ground. A resistor is connected between and in series with the first and second current sources, and a reference voltage is generated across the resistor by the current from the first current source. A first transistor is connected between the ground and a first node located between the resistor and the second current source. A current mirror circuit is connected between the supply voltage and the first transistor. A current sense transistor is connected between the current mirror circuit and an output terminal. An output transistor is connected between the supply voltage and the output terminal. The output voltage generated at the output terminal is equal to the reference voltage. | 04-22-2010 |
20110025280 | REGULATOR HAVING PHASE COMPENSATION CIRCUIT - A regulator circuit includes an output transistor that generates an output current in accordance with a control voltage that is applied to a control terminal of the output transistor. A differential amplifier provides feedback control of the control voltage in accordance with a level of the output current. A phase compensation circuit is connected to the differential amplifier and the control terminal of the output transistor. The phase compensation circuit adjusts an output impedance of the differential amplifier. The phase compensation circuit includes a variable resistor that decreases the output impedance of the differential amplifier when the output current increases. | 02-03-2011 |
20110025419 | DIFFERENTIAL AMPLIFIER WITH OFFSET VOLTAGE TRIMMING - A differential amplifier that has a current supply and a differential current to voltage converter with a positive current input node, a negative current input node and a voltage output node, has offset voltage trimming. The voltage output node provides an output voltage that is proportional to the difference in current values flowing into the positive current input node and a negative current input node. A trimming circuit has a plurality of trimming control inputs, an inverting trimming output, a non-inverting trimming output and trimming inputs coupled to the current supply. Trimming resistances couple the inverting trimming output to the non-inverting trimming output. Trimming selectors, controllable by a trim code provided to the trimming control inputs, provide for selectively connecting the current supply directly to the non-inverting trimming output while selectively connecting the current supply to the inverting trimming output through a first selected group of the trimming resistances. The differential amplifier also has a differential transistor pair formed by an inverting transistor that couples the inverting trimming output to the positive current input node and a non-inverting transistor that couples the non-inverting trimming output to the negative current input node. | 02-03-2011 |
20110050272 | METHOD AND CIRCUIT FOR TESTING INTEGRATED CIRCUIT - A test controller switches the operation of output stages in an integrated circuit between a normal operation mode and a test mode. The output stages are respectively connected to switch elements. A level shifter generates a switch signal for controlling activation and deactivation of the switch elements in accordance with the normal operation mode and the test mode. | 03-03-2011 |
20110050470 | DIGITAL-TO-ANALOG CONVERTER - A DAC unit, connected to a current supply transistor, includes first control transistors connected in parallel to each other, with each being connected in series to the current supply transistor. The first control transistors drive currents at different current values in response to a bias voltage. The DAC unit also includes second control transistors connected in parallel to each other, with each being connected in series to the current supply transistor. Each second control transistor drives the current having the same current value as one of the first control transistors in response to the single bias voltage. The first and second control transistors driving the currents having the same current value operate in a complementary manner based on part of a digital code. The DAC unit generates an output current by selectively combining at least one of the currents driven by the first control transistors. | 03-03-2011 |
20110068851 | POWER SWITCH CIRCUIT - A power switch circuit includes a first switch transistor connected to a main power supply, which supplies a first voltage, a second switch transistor connected in series to the first switch transistor and to a backup power supply, which supplies a second voltage. A switch control unit controls activation and deactivation of the first and second switch transistors so that either one of a voltage corresponding to the first voltage and a voltage corresponding to the second voltage is selectively output to a connection node between the first and second transistors. The first switch transistor includes a first diode, which is formed so that a direction from the main power supply toward the connection node defines a forward direction, and a second diode, which is formed so that a direction from the connection node toward the backup power supply defines a forward direction. | 03-24-2011 |