Seiko Instruments Inc

Sii Semiconductor Corporation

Yotaro Nihei

Takashi Imura

Teruo Suzuki

Takao Nakashimo

Minoru Sudou

Manabu Fujimura

Tadashi Kurozo

Daiki Endo

Akihito Yahagi

Tomoyuki Yokoyama

Provided is a voltage regulator which consumes low power and uses an NMOS transistor as an output transistor. A delay circuit includes, between a constant current circuit and a capacitor, a depletion type NMOS transistor having a gate and a back gate each connected to a ground terminal, the constant current circuit including a depletion type NMOS transistor and a resistor connected between each of a gate and a back gate of the depletion type NMOS transistor and a source thereof.

Delay circuit, oscillation circuit, and semiconductor device

Provided is a voltage regulator capable of suppressing excessive overshoot at the output terminal when the power supply fluctuates in a non-regulate state. The voltage regulator includes: an error amplification circuit that amplifies a difference between reference voltage and divided voltage, thus controlling a gate of an output transistor; an amplifier that compares the reference voltage and the divided voltage to detect overshoot at the output voltage; a first transistor that lets current that is proportional to current flowing through the output transistor pass therethrough; a current mirror circuit that mirrors current that is proportional to the current flowing through the output transistor; and a first bias circuit connected to the amplifier via the current mirror circuit, the first bias circuit increasing bias current of the amplifier to increase a response speed.

Voltage regulator

There is provided a voltage regulator equipped with a reverse-current prevention function capable of ensuring safe performance without causing a large overshoot at an output terminal against a sharp fluctuation in source voltage. The voltage regulator provides a source voltage fluctuation detecting circuit for detecting a fluctuation in source voltage in a comparison circuit for comparing the source voltage with output voltage so that when the source voltage rises sharply, the current through constant current circuits for limiting the consumption current of the comparison circuit will be increased to improve the response characteristics.

Voltage regulator with improved reverse current protection

Provided is a voltage regulator including an overcurrent protection circuit using a simple circuit. The voltage regulator includes the overcurrent protection circuit including: a first sense transistor having a gate connected to an output terminal of an error amplifier circuit and a drain connected to a sense resistor; a second sense transistor having a gate connected to the output terminal of the error amplifier circuit; and a control transistor having a gate connected to an output terminal of a control circuit, a source connected to a drain of the second sense transistor, and a drain connected to the sense resistor, in which the control transistor is turned on in response to a detection signal output by the control circuit until a reference voltage exceeds a predetermined voltage.

Provided is a voltage regulator having low current consumption, which is capable of preventing a reverse current from flowing thereto from an output terminal (), irrespective of a magnitude of a voltage of a VDD terminal (). The voltage regulator has a circuit configuration in which voltage dividing resistors are not used for a comparator circuit for comparing the voltage of the VDD terminal () with a voltage of the output terminal (), to thereby achieve lower current consumption.

Provided is a voltage regulator capable of setting an accurate short-circuit current. Used as a circuit for determining a current value of a short-circuit current of an overcurrent protection circuit is not a resistor for converting current into voltage but a circuit for controlling in the form of current, that is, a circuit of an N-channel depletion type transistor including a gate and a drain that are connected to each other and operating in a non-saturated state. The N-channel depletion type transistor has process fluctuations that are linked with those of a detection transistor, and hence an accurate short-circuit current may be set without trimming.

Provided is a voltage regulator capable of performing appropriate phase compensation. Even when a difference between an input voltage and an output voltage is small, an appropriate phase compensation voltage based on an output voltage (Vout) is generated in a resistor circuit (), and the appropriate phase compensation voltage is applied to a phase compensation capacitor (). Accordingly, the voltage regulator is capable of performing appropriate phase compensation.

Growing community of inventors

Chiba, Japan

Yotaro Nihei