Rohm Co., Ltd.

Seiji Takenaka

Tetsuo Tateishi

Masashi Nagasato

Takuya Ishida

There are disposed second and third transistors whose gates are connected to each other, and first and fourth transistors whose gates are connected to each other. Sources of the first to fourth transistors are connected to each other. A read operation is performed in a state where drain current is supplied to the fourth transistor, and drain current larger than that of the fourth transistor is supplied to the third transistor. In the read operation, a signal associated with a first or second value is output based on drain currents of the first and second transistors.

Non-volatile memory

A non-volatile memory includes a memory cell having a first transistor and a second transistor, a driving circuit arranged to apply a read voltage to gates of the first and second transistors, and a signal output circuit arranged to output a signal associated with a first value or a signal associated with a second value, based on drain currents of the first and second transistors, in a read operation in which the read voltage is applied. The second transistor is constituted of a parallel circuit of a plurality of unit transistors, and gate width of each of the unit transistors is larger than that of the first transistor.

A non-volatile memory has: a first and a second transistor having their gates connected together; a resistor having a first and a second terminal, with the first terminal connected to the source of the first transistor; a read voltage feed circuit configured to feed a read voltage for turning on at least one of the first and second transistors to between the gate of the first transistor and the second terminal of the resistor and to between the gate and the source of the second transistor; and a signal output circuit configured to output, in a read operation in which the read voltage feed circuit feeds the read voltage, a signal associated with a first or second value based on the drain currents of the first and second transistors.

An OTP readout circuit includes an OTP circuit having a first OTP cell in which data is programmable only once, and a readout-possible signal output unit configured to generate a readout-possible voltage for reading out the data and output the generated readout-possible voltage to the OTP circuit. The readout-possible voltage from the readout-possible signal output unit causes the OTP circuit to read out the data programmed into the first OTP cell.

Semiconductor device, OTP readout circuit, and OTP circuit

This switching power sourcehas: a switching output circuitwhich drives an inductor current IL by turning on and off an upper switchand a lower switchand generates an output voltage VOUT from an input voltage PVDD; a lower current detection unitwhich detects the inductor current IL flowing through the lower switchduring an ON-period of the lower switchand acquires lower current feedback information Iinfo; an error amplifierwhich outputs voltage feedback information Vinfo including information on an error between the output voltage VOUT (feedback voltage FB) and a reference voltage REF; an information synthesis unitthat generates synthesis feedback information VIinfo by synthesizing Iinfo with Vinfo; and an information holding unitwhich samples Vinfo during the ON-period of the lower switch

Switching power supply, semiconductor integrated circuit device, and differential input circuit

A switching power supply includes: a switching output circuit configured to generate an output voltage from an input voltage by charging a capacitor by turning on and off an output transistor; a control circuit configured to halt the driving of the switching output circuit when charging electric charge to the capacitor per switching event is limited to a lower limit value and the output voltage, or a feedback voltage commensurate therewith, is raised from a predetermined reference voltage; and a lower limit value setting circuit configured to variably control the lower limit value during the driven period of the switching output circuit. For example, the lower limit value setting circuit can increase the lower limit value with increase in the number of times of switching.

Switching power supply operable in an intermittent driving mode

A switching power supply circuit includes a switching output unit that generates an output voltage from an input voltage using an output transistor, a switching control unit that controls on and off of the output transistor so that the output voltage or a feedback voltage in proportion to the output voltage agrees with a predetermined reference voltage, and one of an interrupt unit and a reference voltage setting unit. The interrupt unit forcibly turns off the output transistor during a period while the output voltage or the feedback voltage is higher than a threshold value voltage that is higher than the reference voltage in response to a periodic load change. The reference voltage setting unit temporarily changes the reference voltage in synchronization with timing of a periodic load change.

Switching power supply circuit, liquid crystal driving device, and liquid crystal display device

A switching power supply circuit has a switching output stage which generates an output voltage from an input voltage by driving a coil current by using an output transistor and a switching controller which turns ON and OFF the output transistor to keep the output voltage or a feedback voltage commensurate with it equal to a predetermined reference voltage. The switching controller includes a reference slope voltage generator which generates a reference slope voltage, a sense voltage holder which generates a held sense voltage by latching a sense voltage commensurate with the coil current with predetermined timing, and a voltage adder which generates a slope voltage by adding up the reference slope voltage and the held sense voltage. The switching controller determines the ON duty of the output transistor by using the slope voltage.

Switching power supply circuit, load driving device, and liquid crystal display device

An oscillation circuit includes: a periodic signal generator which generates a periodic signal whose frequency varies; and a clock generator which generates a clock signal having a frequency commensurate with the frequency of the periodic signal.

Oscillation circuit

A switching power supply circuit has: a switching output generator that generates an output voltage from an input voltage by using an output transistor; a switching controller that turns ON and OFF the output transistor so as to keep the output voltage, or a feedback voltage commensurate therewith, with a predetermined reference voltage; and a maximum duty controller that varies the maximum duty of the output transistor according to the reference voltage, the output voltage, or the feedback voltage.

An error amplifier amplifies a difference between a feedback signal Vthat corresponds to an output voltage Vof a DC/DC converter and its target value V, so as to generate an error signal V. A pulse width modulator for each channel is configured as a peak current mode modulator comprising a PWM comparator that compares a current detection signal Vwith the error signal V, and a logic circuit. When the number of enabled channels is switched, a soft shedding circuit selects at least one channel as a correction target channel. The soft shedding circuit generates a correction signal Vfor each correction target channel, and superimposes each correction signal Von at least one of two inputs of the corresponding PWM comparator.

DC/DC converter

A floppy disk control circuit enables a floppy disk apparatus to operate at high speed while current consumption is suppressed to no more than 500 mA, i.e. the maximum allowed current of an apparatus using a USB interface. The floppy disk control circuit outputs a reference clock to a spindle motor drive circuit that drives the spindle motor in accordance with the reference clock to rotate a floppy disk. The floppy disk control circuit outputs a slow reference clock for a low rotational speed corresponding to the maximum allowed current at the commencement of the start-up of rotation of the floppy disk and outputs a fast reference clock for a high rotational speed after lapse of a predetermined time from the commencement of the start-up of rotation.

Floppy disk control circuit and floppy disk apparatus

A floppy disk apparatus improves power efficiency and quietness by commencing rotation of a stepping motor in a smooth fashion. The floppy disk apparatus includes an interface control circuit that outputs, in accordance with an instruction from a host apparatus, a first step pulse signal, step pulse period signals that indicate the period of the first step pulse signal and that are output before the first step pulse signal and a direction signal, and a floppy disk control circuit that generates a second step pulse signal delayed by a predetermined time from the first step pulse signal in accordance with the step pulse period signal, that generates a first signal that toggles in synchronization with the first step pulse signal and a second signal that toggles in synchronization with the second step pulse signal, and that outputs the first and second signals as control signals in accordance with the direction signal.

Growing community of inventors

Kyoto, Japan

Seiji Takenaka