Rohm Co., Ltd.

Yosuke Fukumoto

Shun Fukushima

Hiroto Oshita

Yuhei Yamaguchi

Tetsuo Tateishi

Kazuhiro Murakami

Genki Tsuruyama

Mikiya Doi

Yoju Imamura

Tadashi Akaho

Takatsugu Wachi

A switching power supply circuit includes: a switching circuit switching an input voltage; a first amplifier generating a first voltage; a first phase compensation circuit including a first capacitor and compensating for a phase of the first voltage; a second amplifier generating a second voltage; a second phase compensation circuit including a second capacitor and compensating for a phase of the second voltage; and a drive control circuit executing a switching operation according to the second voltage, wherein the switching power supply circuit operates in a first or second mode, the drive control circuit performs, in the first mode, the switching operation, and stops, in the second mode, the switching operation, and when returning from the second mode to the first mode, a specific voltage corresponding to an output voltage is supplied to the second capacitor and a predetermined voltage is supplied to the first capacitor.

Switching power supply circuit and switching power supply device

A pulse control devicecomprises: a switch output unitwhich generates a pulse output voltage Vo from a direct-current input voltage Vi and supplies the pulse output voltage Vo to a load (such as a relay coilof a mechanical relay); a low-pass filter unitwhich receives a feedback input of the pulse output voltage Vo and generates a feedback voltage Vfb; and an output feedback control unitwhich receives an input of the feedback voltage Vfb and controls the switch output unitso that an average value of the pulse output voltage Vo becomes constant. The low-pass filter unitmay be configured without a coil.

Pulse control device

There is provided a switching power supply device, including: an output stage circuit including an output transistor installed between an application end of an input voltage and an application end of an output voltage, and configured to generate the output voltage from the input voltage through a switching operation including an operation of switching the output transistor; and a main control circuit configured to execute PWM control for causing the output stage circuit to perform the switching operation at a predetermined PWM frequency based on a feedback voltage according to the output voltage.

Switching power supply device

Disclosed are a power supply control device and an electronic apparatus. The power supply control device includes a power supply unit configured to generate an output voltage from an input voltage, and an output discharge unit configured to start to discharge the output voltage when an instruction to disable the power supply unit is given, and continue discharging the output voltage until the output voltage falls below a predetermined threshold voltage or until a predetermined delay time passes while the output voltage does not fall below the threshold voltage even when an instruction to enable the power supply unit is given. The electronic apparatus includes a power supply device including the power supply control device as a main constituent, and at least one load configured to operate while supplied with an output voltage from the power supply device.

Power supply control device to discharge an output voltage at a time of enable instantaneous interruption

A main control circuit includes a PWM comparator that compares a contrast voltage generated according to a feedback voltage with a ramp voltage having a periodically varying voltage value, and causes an output stage circuit to perform a switching action based on a result of the comparison in the PWM control. A feedback path switch is inserted in a feedback path for propagating a signal according to the feedback voltage to the PWM comparator. The main control circuit controls, upon switching from sleep control that stops the switching action to the PWM control, within a specific period equal to one or more periods of the PWM control, the feedback path switch off and sets a voltage within a variation range of the ramp voltage as an initial voltage for the contrast voltage to thereby start a switching action and controlling the feedback path switch on after the specific period.

A single-line serial data transmission circuit having a master circuitand a slave circuit, the master circuithaving a data clock adderfor writes and a data receiverfor reads. The slave circuithas an active generator, a data clock separatorfor writes, and a data transmitterfor reads. The master circuitand the slave circuitare connected by one length of a signal line. When the master circuitwrites data to the slave circuit, a signal synthesized from a clock signal and a data signal is transmitted to the slave circuitvia the signal lineby the master circuit, and the clock signal and the data signal are extracted from the transmitted signal in the slave circuitthrough the data clock separator

Single-line serial data transmission circuit and single-line serial data transmission method

A switching power supply device has a switching output stage generating an output voltage from an input voltage by switching operation and a controller controlling the switching output stage based on a feedback voltage commensurate with the output voltage. The switching power supply device can perform switching suspension control whereby it stops switching operation on detecting a light-load condition based on the feedback voltage, though it restarts switching operation on detection of an overvoltage condition during suspension of switching operation.

Switching power supply device and semiconductor device

A control device serves as an agent that controls a switching regulator including an output switch and a synchronous rectification switch. The control device includes: a summator generating a sum sense signal by adding up a first sense signal commensurate with the current passing in the output switch and a second sense signal commensurate with the current passing in the synchronous rectification switch; a smoother generating a smoothed sense signal by smoothing the sum sense signal; and a switch driver driving the output switch and the synchronous rectification switch complementarily through current mode control based on the smoothed sense signal.

Switching regulator and control device therefor

The switching regulator has: a control unit for turning on/off an upper switch and a lower switch in a complementary manner in accordance with an output voltage; and a current extraction unit for extracting a constant current from a first end or a second end of an inductor. When under a light load, the control unit stops the switching control and fixes the upper switch and the lower switch in an off state. The constant current has positive temperature characteristics, wherein the value of the constant current is greater than or equal to a value obtained by subtracting leakage current of the lower switch from leakage current of the upper switch.

Switching regulator, semiconductor integrated circuit, and electronic appliance

A switching power supply device includes: a switching output circuit configured to generate an output voltage from an input voltage; an oscillation circuit configured to generate a clock signal; a control circuit configured to control driving of the switching output circuit in synchronization with the clock signal; a pulse-by-pulse type overcurrent protection circuit configured to detect an overcurrent flowing through the switching output circuit to generate an overcurrent protection signal for forcibly stopping a switching operation of the switching output circuit; and a pulse skip circuit configured to perform a pulse skip operation of the clock signal in response to the overcurrent protection signal.

Switching power supply device having pulse-by-pulse type overcurrent protection function

A switching power source apparatus includes: a switching output circuit that generates an output voltage from an input voltage; an error amplifier that generates an error voltage in accordance with a difference between a predetermined reference voltage and the output voltage or a feedback voltage corresponding to the output voltage; a clock signal generation circuit that generates a clock signal; a slope voltage generation circuit that receives the clock signal to generate a slope voltage; a delay circuit that delays the clock signal to generate an on-signal; a PWM comparator that compares the error voltage and the slope voltage with each other to generate an off-signal; a logic circuit that receives the on-signal and off-signal to generate a pulse width modulation signal; and a switch drive circuit that receives the pulse width modulation signal to generate a drive signal for the switching output circuit.

Switching power source apparatus

A switching power supply device includes a switching output circuit, an error amplifier, a slope voltage generating circuit, a PWM comparator, a logic circuit, a switch driving circuit, and a reverse current detection circuit. The slope voltage generating circuit increases a slope voltage from a reset level with a gradient corresponding to an input voltage during an on period of the output transistor, and maintains the slope voltage at an offset level corresponding not to the reset level but to an output voltage during an off period of the output transistor.

A switching regulator includes a load determination circuit. The load determination circuit feeds, to an offset voltage generation circuit, a different load determination signal at the time of light load or at the time of heavy load. The offset voltage generation circuit applies an offset voltage corresponding to whether a load is light or heavy to the inverting input terminal of a PWM comparator to acquire the responsiveness and the stability of the switching regulator.

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Kyoto, Japan

Yosuke Fukumoto