Rohm Co., Ltd.

Ryo Takagi

Akira Aoki

Masaaki Nakayama

Koji Takahata

Daisuke Kanbara

A level shifter includes a current output amplifier configured to output a first output current and a second output current through first and second output terminals thereof, respectively, a first resistor configured to be connected between each of an inverted input terminal and the first output terminal of the current output amplifier and an application terminal of a ground potential, and a second resistor configured to be connected between the second output terminal of the current output amplifier and an application terminal of a negative potential lower than the ground potential. A first analog signal referenced to the ground potential is accepted at a non-inverted input terminal of the current output amplifier, and a second analog signal referenced to the negative potential is outputted through one terminal of the second resistor.

Level shifter, semiconductor device, switching power supply, and light emitting device

A light-emitting element driving circuit device in which the light-emitting element driving circuit device includes: a clock signal generator configured to generate a clock signal that drives high-side and low-side transistors of a switching output stage to turn them on and off complementarily; a first comparator configured to sense a voltage appearing across terminals of a current sense resistor; a light-emitting element current sense circuit configured to sense a light-emitting element current passing through the current sense resistor; and a duration determining circuit configured to measure a duration of a high level or a low level in the switching signal, in which the light-emitting element driving circuit device is configured to output a notification as to whether a connection status of a light-emitting element is good or bad based on a comparator output signal from the first comparator and an output from the duration determining circuit.

Light-emitting element driving control device and light-emitting element driving circuit device

A power control device is configured to control a power circuit that generates an output voltage based on an input supply voltage relative to a ground, and includes a first terminal fed with a common voltage, a second terminal connectable to an application terminal for the ground, a P-type substrate fed with the common voltage, a MOS transistor connected between the first and second terminals and configured with an N-channel MOSFET, and an internal reference voltage generating circuit configured to generate, based on the input supply voltage, an internal reference voltage relative to the common voltage. When the input supply voltage is turned on, the MOS transistor is turned on and thereby the first and second terminals are short-circuited together.

Power control device

This light-emitting element drive control device () comprises: a drive logic unit () which performs a drive control of a switch output stage (N, D, L) for dropping an input voltage (VIN) to an output voltage (VOUT) and supplying a light-emitting element therewith; a charge-pump power supply unit (α) which generates a step-up voltage (CP) higher than the input voltage (VIN); and a current detecting comparator () which receives a supply of the step-up voltage (CP) and the output voltage (VOUT) as power supply voltages, and generates control signals (SET, RST) for the drive logic unit () by directly comparing a current detection signal (Vsns) corresponding to an inductor current (IL) of the switch output stage with a peak detection value (Vsns_pk) and a bottom detection value (Vsns_bt).

A lighting control device switches an input voltage to generate an output voltage and supplies a driving current based on the output voltage to a lighting unit. A raw control signal is generated to specify a lighting period and an extinction period alternately, and a corrected control signal is generated by correcting the raw control signal based on the current through the lighting unit. A switching controller performs the switching of the input voltage during the lighting period specified by the corrected control signal and suspends the switching of the input voltage during the extinction period specified by the corrected control signal.

Lighting control device, lighting device, and vehicle

This light-emitting element drive control device () comprises: a drive logic unit () which performs a drive control of a switch output stage (N, D, L) for dropping an input voltage (VIN) to an output voltage (VOUT) and supplying a light-emitting element therewith: a charge-pump power supply unit (&#x3b1;) which generates a step-up voltage (CP) higher than the input voltage (VIN); and a current detecting comparator () which receives a supply of the step-up voltage (CP) and the output voltage (VOUT) as power supply voltages, and generates control signals (SET, RST) for the drive logic unit () by directly comparing a current detection signal (Vsns) corresponding to an inductor current (IL) of the switch output stage with a peak detection value (Vsns_pk) and a bottom detection value (Vsns_bt).

Light-emitting element driving control device

This light-emitting element drive control device () comprises: a drive logic unit () which performs a drive control of a switch output stage (N, D, L) for dropping an input voltage (VIN) to an output voltage (VOUT) and supplying a light-emitting element therewith; a charge-pump power supply unit (a) which generates a step-up voltage (CP) higher than the input voltage (VIN); and a current detecting comparator () which receives a supply of the step-up voltage (CP) and the output voltage (VOUT) as power supply voltages, and generates control signals (SET, RST) for the drive logic unit () by directly comparing a current detection signal (Vsns) corresponding to an inductor current (IL) of the switch output stage with a peak detection value (Vsns_pk) and a bottom detection value (Vsns_bt).

A light emitting element driving device includes, for example, a slope voltage generator generating a slope voltage including information on an inductor current passing through a switching output stage, a sense amplifier generating a sense voltage commensurate with the output current fed to a light-emitting element from the switching output stage, a sense amplifier generating a control voltage commensurate with the difference between the sense voltage and a reference voltage, a comparator comparing the slope voltage with the control voltage to generate a comparison signal, a controller controlling the switching output stage in accordance with the comparison signal, and a clamper limiting the control voltage to equal to or lower than a clamp voltage commensurate with the slope voltage.

Light emitting element driving device

A light emitting element drive device generates a single output current while switching a target current value for each of a plurality of light emitting elements, and supplies the single output current to the plurality of light emitting elements in a time division manner.

Light emitting element drive device

A class D power amplifier includes: a signal input terminal for receiving an analog signal; an analog signal processing unit for amplifying the analog signal; an integrating circuit for integrating the analog signal received from analog signal processing unit; a PWM circuit for providing pulse width modulation to an integration signal received from the integrating circuit, and outputting a resulting pulse width modulation signal having a duty ratio falling within a first duty ratio range; a duty ratio adjusting circuit for adjusting the pulse width modulation signal, received from the PWM circuit, to have a pulse width falling within a second duty ratio range narrower than the first duty ratio range; a first driver and a second driver each for processing the pulse width modulation signal received from the duty ratio adjusting circuit; and power transistors.

Class D power amplifier

A class-D power amplifier according to the present invention includes: a pulse width modulation circuit which modulates an analog signal into low-level and high-level binary signals; and a detection circuit which turns off operation of a circuit connected with a back stage of the pulse modulation circuit if the high level or the low level of the binary signal output from the pulse width modulation circuit is maintained for a predetermined time.

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Kyoto, Japan

Ryo Takagi