Seiko Instruments Inc

Ablic Inc.

Sii Semiconductor Corporation

Takao Nakashimo

Takashi Imura

Tadashi Kurozo

Masakazu Sugiura

Hiroshi Mukainakano

Atsushi Igarashi

Teruo Suzuki

Michiyasu Deguchi

Yuji Kobayashi

Atsuo Fukui

Yotaro Nihei

Masahiro Mitani

Provided is an overheat detection circuit capable of easily adjusting a detection temperature of the overheat detection circuit. The overheat detection circuit includes: a first resistor; a second resistor, which has the same temperature characteristics with the first resistor, and has an adjustable resistance value; and a heat sensitive element connected to one end of the second resistor, in which a first current, which is based on a first voltage, is supplied to the first resistor, a current, which is proportional to the first current, is supplied to the second resistor so that a second voltage is generated at another end of the second resistor, and when the first voltage and the second voltage are compared, a result of the comparison is output as an overheat detection signal.

Overheat detection circuit, overheat protection circuit, and semiconductor device

A semiconductor circuit converts an applied input voltage into a desired output voltage and outputs the same from a voltage output terminal. A first resistor, a second resistor, and a third resistor are connected in series between the voltage output terminal and a ground terminal. When a switch is brought to an open state, an output voltage based on a voltage divided by a combined resistance of the second and third resistors and the first resistor is supplied. When the switch is brought to a closed state, an output voltage based on a voltage divided by the second and first resistors is supplied. The semiconductor circuit has a configuration of controlling the resistance value of each voltage division resistor by a control signal from the outside.

Semiconductor circuit

The voltage regulator includes a reference voltage circuit configured to feed back the reference voltage as a feedback voltage and to output the reference voltage, a soft-start circuit configured to output a control signal for controlling the reference voltage to rise linearly at a start of power supply, a voltage divider circuit configured to output a divided voltage, an error amplifier circuit configured to amplify and output a difference between the reference voltage and the divided voltage, and an output transistor controlled by an output voltage of the error amplifier circuit. The reference voltage circuit includes an analog switch transistor having a gate controlled by the control signal, and the feedback voltage is an output voltage from the analog switch transistor.

Voltage regulator with reference voltage soft start

Provided is a temperature detection circuit having less manufacturing fluctuations in detection temperature and capable of easily adjusting the manufacturing fluctuations in detection temperature. The temperature detection circuit includes: a constant current circuit configured to output a constant current; a voltage-controlled current circuit, which is controlled by a voltage output from a heat sensitive element and is configured to output a current corresponding to temperature; and a current comparator configured to compare the constant current and the current corresponding to temperature, and output a detection signal indicating that a predetermined temperature is detected. Temperature characteristics of the constant current circuit and temperature characteristics of the voltage-controlled current circuit have a correlation with each other. The temperature detection circuit is configured to detect temperature based on a result of comparing the output current of the constant current circuit and the output current of the voltage-controlled current circuit.

Temperature detection circuit and semiconductor device

Provided is a voltage regulator having a simple circuit configuration in which a protection circuit is not erroneously operated, and delay time of activation of the protection circuit is short. The voltage regulator includes: a protection circuit configured to control an output transistor when an abnormality of the voltage regulator is detected; a first constant current circuit configured to supply operating current to the protection circuit; and a detection circuit configured to detect output current flowing through the output transistor, to thereby control the first constant current circuit. The detection circuit is further configured to detect the output current with a predetermined reference current value. The protection circuit is further configured to control the output transistor so that the output current does not fall below the reference current value.

Short activation time voltage regulator

Provided is a voltage regulator that is low in current consumption and is capable of suppressing the occurrence of an excessive overshoot at an output terminal when a power supply voltage becomes high in a non-regulated state. The voltage regulator includes: an overshoot limiting circuit for detecting an occurrence of an overshoot in an output voltage and limiting a current of the output transistor; and a non-regulated state detection circuit for detecting a non-regulated state of the voltage regulator based on a voltage of an output terminal and a current flowing through the output transistor. The overshoot limiting circuit has an operating current controlled by a detection signal of the non-regulated state detection circuit.

Voltage regulator

Provided is a power supply integrated circuit including an overheat protection circuit with high detection accuracy. The overheat protection circuit includes: a current generation circuit including: a first metal oxide semiconductor (MOS) transistor including a gate terminal and a drain terminal that are connected to each other, the first MOS transistor operating in a weak inversion region; a second MOS transistor including a gate terminal connected to the gate terminal of the first MOS transistor, the second MOS transistor having the same conductivity type as the first MOS transistor and operating in a weak inversion region; and a first resistive element connected to a source terminal of the second MOS transistor; and a comparator for comparing a reference voltage having positive temperature characteristics and a temperature voltage having negative temperature characteristics, which are obtained based on a current generated by the current generation circuit.

Overheat protection circuit and power supply integrated circuit

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 in which a maximum output current and a short-circuit output current may be accurately set. As a circuit for determining respective current values of a maximum output current (Im) and a short-circuit output current (Is) of an overcurrent protection circuit, the voltage regulator includes a current mirror circuit for mirroring a current in accordance with an output current so as to be capable of current control, without employing a resistor for converting a current into a voltage. Therefore, the maximum output current (Im) and the short-circuit output current (Is) may be accurately set with respect to an output current (Iout).

Voltage regulator with an overcurrent protection circuit

A voltage regulator has a first error amplifier circuit that amplifies a difference between a first reference voltage and a voltage based on an output voltage of an output transistor, and an overcurrent protection circuit that detects an overcurrent flowing through the output transistor and limits a current of the output transistor. The overcurrent protection circuit has an output current detection transistor that feeds a detection current in accordance with an output current of the output transistor, a voltage generation circuit that generates a voltage based on the detection current, a second error amplifier circuit that amplifies a difference between the voltage from the voltage generation circuit and a voltage set by a second reference voltage supplied by a temperature detection circuit and a voltage based on the output voltage, and an output current limiting transistor that controls a gate voltage of the output transistor and has a gate that is controlled by an output of the second error amplifier circuit.

Provided is a voltage control circuit which suppresses a calorific value that generates when short-circuit fault occurs even if a voltage value of an input voltage is large. At the time of short-circuit fault, an additional control voltage Va whose voltage value becomes larger when the voltage value of the input voltage Vin is larger is input to the voltage control p-channel MOS transistor () from a transistor control MOS transistor (), to thereby increase resistance of the voltage control p-channel MOS transistor () to suppress a short-circuit current. As a result, when the input voltage Vin is larger, the current value of a holding current or a calorific value after the short-circuit protecting operation has been conducted can be suppressed.

Voltage control circuit

A charging and discharging control circuit is provided in which a delay circuit is built in an over-discharge detector circuit, an over-charge detector circuit, or the like. A delay time of the detector circuit can be changed from an external without adding a control terminal, thereby reducing a test time of the detector circuit. A voltage detector circuit is disposed between a power supply terminal and a power supply voltage detection terminal of the charging and discharging control circuit, and the voltage detector circuit detects a specified voltage or higher, to thereby shorten the delay time of the internal control circuit.

Charge and discharge control circuit with variable switching delay time function and charging-type supply device using the control circuit

A reduced power consumption diode circuit has a first voltage comparator that compares a voltage at a cathode terminal with a first sum of a voltage at an anode terminal and a voltage across a second voltage source, and outputs a reset signal. A second voltage comparator compares the voltage at the anode terminal with a second sum of the voltage at the cathode terminal and a voltage across the first voltage source, and outputs a set signal. A first latch circuit outputs a low level signal when the reset signal is input and a high level signal when the set signal is input. A diode has an anode connected to the anode terminal and a cathode connected to the cathode terminal, and an n-channel MOS transistor turns off in response to the low level signal and turns on in response to the high level signal.

Diode circuit

A reference voltage circuit is provided in which a difference of voltages applied to reference voltage circuits is reduced so that a difference of respective output voltages is made small. Depletion type MOS transistors ( ) are respectively connected in series with the drains of depletion type MOS transistors ( ) in two ED type reference voltage circuits. The gate of one of the series-connected depletion type MOS transistors ( ) is connected with the source of the other MOS transistor and the gate of the other MOS transistor is connected with the source of the one MOS transistor. Thus, a difference of voltages applied to the respective ED type reference voltage circuits is reduced so that a difference of respective output voltages is made small.

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Chiba, Japan

Takao Nakashimo