Panasonic Intellectual Property Management Co., Ltd.

Panasonic Corporation

Nuvoton Technology Corporation Japan

Takashi Saji

Kensuke Takahashi

Tatsuya Sakurai

Yoshihiro Mori

Kaname Motoyoshi

Hiroto Yamagiwa

Shingo Matsuda

Keita Kawabe

Koji Suzuki

Kazuhiro Murata

Yoshihisa Minami

Tetsuji Yamashita

Tetsuyuki Fukushima

Naohiko Morota

Toshifumi Ishida

Saichiro Kaneko

Tomoko Usukura

Masatoshi Tanioku

A power amplifier device includes: a first power supply terminal for inputting a first power supply voltage; a first transistor for power amplification that (i) includes a first gate to which a bias voltage is applied, and (ii) is supplied with power from the first power supply terminal; a second power supply terminal for inputting a second power supply voltage lower than the first power supply voltage; a second transistor for monitoring that (i) includes a second gate to which the bias voltage is applied, (ii) is supplied with power from the first power supply terminal or the second power supply terminal, and (iii) imitates an operation of the first transistor; and a bias circuit that is supplied with power from the second power supply terminal and generates and adjusts the bias voltage according to a drain current or a source current of the second transistor.

Power amplifier device

In a switching power supply device including an overload protection circuit, when a load state turns into an overload state due to a decrease in an input voltage, an overload protection signal is activated in response to activation of an overload detection signal, and the overload protection signal is deactivated when an input low voltage detection signal is in an inactive state.

Switching power supply device and semiconductor device

A switching power supply device includes: a rectifier circuit to which an AC input voltage is input; an input smoothing circuit smoothing a DC input voltage output from the rectifier circuit; a power converter circuit converting the DC input voltage and outputs an output voltage; an overvoltage detection circuit generating an input overvoltage detection signal which is activated when the DC input voltage is higher than a first reference voltage level; and a discharge circuit discharging stored charge stored in the input smoothing circuit. The power converter circuit includes a switching element. Switching of the switching element is stopped and discharging of the stored charge is started, with activation of the input overvoltage detection signal serving as a trigger, and when the input overvoltage detection signal is subsequently inactivated, the discharging is stopped and the switching of the switching element is resumed.

A switching power supply apparatus includes a PFM control circuit that outputs a clock signal Set such that a switching frequency of a switching element varies in accordance with a load state. The clock signal Set determines a turn-on timing of the switching element. A reference value of a current flowing through the switching element determines a turn-off timing of the switching element. A modulation signal is applied to the turn-off timing of the switching element to modulate one of a peak value of a drain current flowing through the switching element and an on-time of the switching element. Input control is performed separately on the clock signal Set and the modulation signal. Accordingly, even when the clock signal Set and the modulation signal contribute to each other to offset each other, modulation effects are not cancelled.

Switching power supply apparatus and semiconductor device

A switching power supply circuit includes an intermittent oscillation control circuit, which performs intermittent oscillation control that repeats a cycle including an oscillation time period and a stop time period according to a feedback signal so that output voltage or current becomes constant, compares an intermittent oscillation period that is a sum of the oscillation time period and the stop time period with a preset target period, sets the oscillation time period of current cycle to a length obtained by extending the oscillation time period of previous cycle by first predetermined time when the intermittent oscillation period is shorter than the target period, and sets the oscillation time period of current cycle to a length obtained by subtracting second predetermined time from the oscillation time period of previous cycle when the intermittent oscillation period is longer than the target period, in each cycle of intermittent oscillation control.

A switching power supply device has both a turn-on timing modulation function and a turn-off timing modulation function, performs the turn-off timing modulation in a PFM control region and the turn-on timing modulation in a PWM control region, and further continues at least one of the modulations even after the PFM control and the PWM control are switched from one to the other, to achieve a stable operation of the switching power supply device at the control switching boundary without significantly decreasing the modulation effect of frequency jitter control.

A direct current power supply circuit includes an alternating-current power supply; a rectification circuit for generating a direct-current voltage from an alternating-current voltage; a charging switch having an input terminal connected to the rectification circuit, the charging switch outputting an output voltage according to an input value input to a control terminal; a capacitor and a control circuit, which are connected to an output terminal; and a charging switch control circuit for generating a switch-on signal when the output voltage is equal to or lower than a first reference voltage value, and for generating a switch-off signal when the output voltage is equal to or higher than a second reference voltage value higher than the first reference voltage value, wherein a charging period setting circuit including at least one of the rectification circuit and the charging switch control circuit sets a charging period in which a charging current flows into the capacitor and a non-charging period in which the charging current does not flow, and in a case where the switch-on signal is generated during the charging period, the charging current flows through the charging switch when the direct-current voltage becomes equal to or higher than the output voltage, and in a case where the switch-on signal is generated during the non-charging period, the charging current does not flow through the charging switch even if the direct-current voltage becomes equal to or higher than the output voltage.

Direct current power supply circuit

A switching power supply device of the present disclosure includes a device connection state detection circuit that detects a connection state in a load device connection terminal, in a power supply system having the load device connection terminal. The device connection state detection circuit includes a transformer, a switching element, a pulse generator, and a waveform detection circuit. The waveform detection circuit detects a voltage or a current generated at a connecting point between a primary winding wire of the transformer and the switching element in response to operation of a pulse signal. The waveform detection circuit compares the voltage or the current with a predetermined reference value, and outputs an output signal in response to a comparison result to an OFF terminal.

Switching power supply device

A switching power supply apparatus of the present disclosure is a device connection state detection circuit that detects a connection state in a load device connection terminal in a power supply system having the load device connection terminal. The device connection state detection circuit includes a transformer, a switching element, a pulse generator, and a waveform detection circuit. The waveform detection circuit detects a voltage or a current generated in a primary winding wire or a secondary winding wire of the transformer in accordance with operation of a pulse signal, compares the detected voltage or current with a preset reference value, and outputs an output signal in accordance with a comparison result, to an OFF terminal.

Switching power supply apparatus

Provided is a switching power supply apparatus that shifts to an OFF mode when electronic equipment is on standby, and includes: an OFF mode delay circuit that delays shifting to the OFF mode; and an electric storage unit and a power supply circuit that function as a power supply source of an OFF mode control circuit. With the configuration, the power consumption can almost be eliminated, and the switching power supply apparatus can start without any charge in an electricity storage component such as a primary battery or a secondary battery.

A converter includes: a bridge diode; an X capacitor provided upstream of the bridge diode; a smoothing capacitor provided downstream of the bridge diode; an AC shutoff detection circuit which outputs an AC shutoff detection signal when input AC voltage is shut off; and a discharging circuit which is connected to a connection point at which the cathode of the bridge diode and the smoothing capacitor are connected, and allows residual charges in the smoothing capacitor and the X capacitor to be discharged when the AC shutoff detection signal is output, and the discharging circuit includes a JFET which has a drain terminal connected to the above connection point and lowers discharge voltage; and a first discharging switch element connected to the source terminal of the JFET.

Growing community of inventors

Shiga, Japan

Takashi Saji