Matsushita Electric Industrial Co., Ltd.

Panasonic Corporation

Tomoya Shigemi

Takuya Ishii

Takashi Ryu

Mikio Motomori

Hirohisa Tanabe

Hiroki Akashi

Makoto Ishimaru

Kazuhito Kimura

Masato Yoshida

Noboru Nakashima

Yoshitaka Ikeuchi

A protection device detects a temperature in a predetermined monitoring place in an electronic apparatusto protect the electronic apparatus, and includes an oscillating circuitfor generating a clock signal Vck having a predetermined cycle and a predetermined ON time, and a temperature detection circuitfor detecting the temperature in the monitoring place during the ON time of the clock signal Vck. The protection device shuts off supply of electric power to the electronic apparatus, when the temperature in the monitoring place exceeds a predetermined temperature.

Protection device, protection method using the same, method for processing signal using the same, and method for detecting quantity of electricity using the same

A step-up converter includes an inductor which receives input voltage Vi at one end, a first FET of the first conduction type which functions as a switch for determining whether or not energy is accumulated in the inductor, a second FET of the second conduction type which rectifies a current output from the other end of the inductor, an output capacitor having an end connected to the source of the second FET, a current detection circuit, and a feedback control circuit. The current detection circuit detects a current flowing through the first N-channel FET to output current detection signal Vc. The feedback control circuit controls the operations of the first N-channel FET and a P-channel FET based on current detection signal Vc.

Step-up converter

A current detection circuit of the present invention has a switching devicean auxiliary switching devicean offset voltage source comprising an offset resistor deviceand a current source circuita compensation circuit, comprising a differential amplifierand a compensation transistorfor adjusting the output current of the auxiliary switching deviceso that the potential obtained by subtracting the voltage drop across the offset resistor devicefrom the output potential of the switching deviceis equal to the output potential of the auxiliary switching devicebeing configured that the detection level of the current flowing in the switching deviceis shifted by an offset amount.

Current detection circuit and switching power supply

In a DC-DC converter conforming to the current mode control system, in which the valley value of an inductor current is controlled for output control, a current detection circuitis configured to detect the current flowing from a low-side FETto an inductorusing an FET, an NPN transistor, an NPN transistor, a PNP transistor, a PNP transistorand a resistor, to detect the current flowing from the inductorto the low-side FETusing an FET, a differential amplifier, an FETand the resistor, and to output a current detection signal Vc.

DC-DC converter

A current detection circuit of the present invention has a switching device; an auxiliary switching device; an offset voltage source comprising an offset resistor deviceand a current source circuit; a compensation circuit, comprising a differential amplifierand a compensation transistor, for adjusting the output current of the auxiliary switching deviceso that the potential obtained by subtracting the voltage drop across the offset resistor devicefrom the output potential of the switching deviceis equal to the output potential of the auxiliary switching device, being configured that the detection level of the current flowing in the switching deviceis shifted by an offset amount.

Current detection circuit and switching power supply using the same

An output detection feedback section () for controlling the power supply output voltage of a converter unit () in response to an error signal Ve has an error amplifier () for outputting the error signal Ve, a phase compensation circuit (), a state detection circuit (), and a response compensation circuit () for setting the voltage of a capacitor () of the phase compensation circuit () to a predetermined value. When output voltage is switched, the output voltage is fixed at the predetermined value in a DC manner while a transitional response of the error signal (Ve) is accelerated, so that the output voltage is changed at a high speed to a desired value and the overshoot and undershoot are suppressed around the desired value.

Power supply

For controlling DC-DC converters conforming to voltage mode control system and current mode control system, in multi-output power supply, first converter sectionis configured that first detection circuitoutputs first control signal, that first oscillation circuitoutputs first triangular wave signal and clock signal, and that first pulse-width modulation circuitdrives first switch by comparing first control signal with first triangular wave signal. Second converter sectionis configured that second detection circuitoutputs second control signal, that second oscillation circuitoutputs second triangular wave signal synchronized with clock signal, that current detection circuitoutputs current signal of second inductor, and that second pulse-width modulation circuitturns ON second switch in synchronization with clock signal and turns OFF second switch by calculating or comparing second control signal, the second triangular wave signal and current signal.

Multi-output power supply and electronic device using them

A DC-DC converter has switching means which generates a continuous switching voltage having a specified period from an input voltage and outputs the generated switching voltage, output voltage generating means which receives the switching voltage at an inductor and generates an output voltage obtained by rectifying and smoothing a voltage generated in the inductor, lamp signal generating means which generates a lamp signal and outputs the generated lamp signal, and control means which performs an arithmetic operation using a current signal relative to a current flowing in the inductor, an error signal relative to the output voltage, and the lamp signal to generate a control signal for controlling the operation of the switching means and outputs the generated control signal to the switching means. The lamp signal generating means includes first signal generating means for generating a first output signal based on a frequency divided signal having first and second periods obtained by dividing the time of a clock signal having the specified period and second signal generating means for generating a second output signal having a phase 180 degrees different from the phase of the first output signal based on the frequency divided signal, generates the lamp signal which rises after being held at a constant value for a specified time period in each of the first and second periods, and outputs the generated lamp signal.

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Osaka, Japan

Tomoya Shigemi