Mitsumi Electric Company Ltd.

Matsushita Electric Industrial Co., Ltd.

Hitachi, Ltd.

Takeshi Sato

Takumi Hyugaji

Minoru Kado

Noriaki Morotomi

Seiji Sakashita

Hiroshi Takahashi

Hiroyuki Nagai

Akira Usui

Kazuhiko Kubo

Satoshi Arima

Yasunobu Ikeda

Keiji Usuba

Kazuo Kobo

Kanta Judai

Takao Iwata

Kiyoshi Kubo

Yoshimi Nakagawa

Satoko Araki

Takumi Hyuugaji

Takashi Kaiho

Yasuhito Okawa

Takao Funahashi

Syuji Aoyama

Kenji Nakata

A switching power supply device includes a secondary-side control circuit including a switching control circuit that generates a voltage for ON-OFF control of a switching element for synchronous rectification. The secondary-side control circuit includes an external terminal to which a drain voltage of the switching element is input, a power supply terminal to which a voltage rectified by the switching element is input, a peak hold circuit that holds a peak of the drain voltage input to the external terminal, and an abnormality detection circuit that operates based on the voltage at the power supply terminal or a voltage derived from the voltage at the power supply terminal and a holding voltage of the peak hold circuit, and outputs an abnormality detection signal when detecting an abnormal state in which the voltage at the power supply terminal decreases or no voltage is input to the power supply terminal.

Switching power supply device

Disclosed is a switching power supply device including: a transformer for voltage conversion; a main switching element connected in series to a primary coil; a primary side control circuit that performs on/off control of the main switching element; a synchronous rectification MOS transistor connected in series to a secondary coil; and a secondary side control circuit that performs on/off control of the MOS transistor, wherein the secondary side control circuit includes: an off-timing detection circuit that compares a drain voltage of the MOS transistor with a predetermined threshold voltage, and detects a timing to turn off the MOS transistor; and a threshold voltage setting circuit that sets the threshold voltage, and the threshold voltage setting circuit sets the threshold voltage based on a conduction period of the secondary coil or a period obtained by adding the conduction period to a conduction period of the primary coil.

Switching power supply device having secondary side synchronous rectification element and control circuit therefor

A switching power supply device includes a transformer for voltage conversion, a synchronous rectification MOS transistor, and a secondary side control circuit. The synchronous rectification MOS transistor is connected in series to a secondary side coil of the transformer. The secondary side control circuit performs on/off control of the synchronous rectification MOS transistor based on a drain voltage of the synchronous rectification MOS transistor. The secondary side control circuit includes a peak period detection circuit and a determination reference voltage generation circuit. The peak period detection circuit detects a peak period of the drain voltage. The determination reference voltage generation circuit generates a reference voltage to be used as a reference for determining the peak period based on a voltage in the peak period. The peak period detection circuit detects the peak period based on the drain voltage and on the reference voltage.

A switching power supply device includes a transformer for voltage conversion, a synchronous rectification MOS transistor, a secondary side control circuit, and a minimum on-time setting circuit. The synchronous rectification MOS transistor is connected in series to a secondary side coil of the transformer. The secondary side control circuit performs on/off control of the synchronous rectification MOS transistor based on a drain voltage of the synchronous rectification MOS transistor. The minimum on-time setting circuit sets a minimum on-time when turning on the synchronous rectification MOS transistor based on a peak period and a bottom period detected by the secondary side control circuit.

An insulated DC power supply includes a voltage transformer, a switching device and a primary-side regulating circuit. The voltage transformer includes primary and secondary windings and an auxiliary winding. The switching device causes current to flow intermittently through the primary winding. The primary-side regulating circuit receives a voltage proportional to a current flowing through the primary winding of the transformer, and a voltage proportional to a voltage induced in the auxiliary winding of the transformer to generate and output a drive pulse for turning on or off the switching device. The primary-side regulating circuit includes an ON/OFF signal generator circuit and first and second timer circuits. The switching device is turned off upon expiration of the first timer circuit, and the ON/OFF signal generator circuit does not generate a signal for turn-on of the switching device when the second timer circuit expires.

Insulated DC power supply and a method of controlling same

A synchronous rectification type DC-DC converter equipped with a burst mode prevents backward flows of currents on the secondary side thereof. The DC-DC converter turns off a control signal of a switching element on the primary side when the load thereof becomes light, and includes a voltage converting transformer, a first switching element connected to the primary side coil of the transformer, a primary side control circuit performing on-off control of the first switching element, a synchronously rectifying second switching element connected to the secondary side coil, and a secondary side control circuit performing on-off control of the second switching element. A pulse width ensuring circuit ensures that the pulse width of the control signal performing on-off control of the first switching element does not become equal to or less than the original width of a PWM pulse when entering the burst mode and when exiting the burst mode.

Switching power supply apparatus and primary side control circuit

A flyback system power source apparatus, which applies a voltage intermittently to a primary winding of a transformer to perform voltage outputting onto a secondary winding side of the transformer, comprises: the transformer; a synchronously rectifying element for rectifying a current in a secondary winding of the transformer; and a synchronous rectification control circuit for detecting a voltage vibration caused in a terminal voltage of the secondary winding to perform operation control of the synchronously rectifying element on the basis of the detection.

Flyback system power source apparatus for controlling a synchronously rectifying element

A voltage detecting circuit to perform voltage detection by introducing a voltage from a detection node, comprises: a first resistance, a second resistance, and a first switching element, connected in series with each other from the detection node to reference electric potential in order; and a detection circuit for performing a detection operation of a voltage by receiving input of the voltage from a node between the first resistance and the second resistance, wherein a control voltage generated on the basis of the voltage at the detection node is supplied to a control terminal of the first switching element, and the first switching element is turned on when the voltage at the detection node is large, and the first switching element is turned off when the voltage at the detection node is small.

Voltage detecting circuit and switching power source apparatus

The invention has an object of enhancing the service capacity and the operability of a network and simplifying the maintenance and control of the network by adopting a size automatic change mode after a path is set and providing arbitrary pathsize at arbitrary time. To achieve the object, the following means is provided. The service capacity and the operability of a network are enhanced and the maintenance and control of the network are simplified by adopting a size automatic change mode that the size of an input path signal conforms to information written to line overhead H1 and H2 bytes and an output path signal is transmitted with the pathsize the same as the size of the input path signal. A case that receiving path size changes exceeding a band and the fault of a path is caused occurs by providing both modes of fixing pathsize and automating pathsize to a user, flexibly corresponding to various service and automatically changing pathsize. At this time, an operation system identifies the cause, analyzes an influenced range and realizes the simplification of the maintenance and control of the network.

Pathsize control method and operation of transmission apparatus

An internal battery ( ) has a battery terminal provided on a tip and has a third engagement projection ( ) provided on the other end in a vertical direction. A battery housing portion ( ) has a connector ( ) provided on a tip and has, on a rear end, a battery hook ( ) for pressing the third engagement projection ( ) interlockingly with a sliding operation from a release position to a lock position. The battery hook ( ) is slid from the release position to the lock position to press the third engagement projection ( ). Consequently, the battery terminal is caused to abut on the connector ( ) and the internal battery is fixed into the battery housing portion ( ). A battery ( ) is fixed and attachment is thus completed.

Internal battery holding structure in mobile equipment

The PLL circuit provides both the advantages of analog phase control, in which a good C/N ratio can be realized, and the advantages of digital phase control, in which broad-band lock can be performed. A multi-channel FM receiving method and apparatus are able to utilize the PLL circuit to reduce the influence of the leakage occurring among input signals and suppress image disturbance. One PLL circuit includes: a VCO; a pre-scaler for dividing a feedback signal obtained from the VCO; a first distributor for distributing the feedback signal to send first and second digital feedback signals; a second distributor for distributing a reference signal to send a digital reference signal and an analog reference signal; a digital phase comparator for comparing the digital reference signal and the first digital feedback signal with each other to send a digital phase error signal; a charge pump; a mixer for adding the digital phase error signal to an analog phase error signal, which is obtained by comparing the analog reference signal with the second digital feedback signal to send a composite phase error signal; and a low-pass filter for eliminating high frequency components from the composite phase error signal to input the resultant signal to the VCO.

PLL circuit having a multiloop, and FM receiving method and apparatus

A frequency conversion apparatus for converting a high frequency signal into an intermediate frequency signal includes a mixer section for mixing a high frequency signal with a local oscillator signal so as to obtain an intermediate frequency signal, and an amplifier connected to the mixer section via a high frequency stopping circuit for supplying a constant direct current to the mixer section as a constant current source. A current flowing in the mixer section when the local oscillator signal is applied is kept substantially equal to a direct current flowing in the mixer section when no local oscillator signal is applied thereto. The amplifier is used for amplifying either the high frequency signal or the intermediate frequency signal, or both signals at the same time.

Frequency conversion apparatus

A digital data reproducing system which carries out quantization by the frequency over the transmission rate with respect to waveform distortion created by a group delay caused by ghosts and repeaters or the like when digital information signals are received so as to thereby perform waveform equalization, and which carries out phase correction to thereby enable data reproduction about equivalent to that quantized by an ideal sampling timing, thus realizing entire digitization of the data reproducing system.

Digital data reproducing system

A ghost canceling apparatus for effectively canceling ghosts in television signals and having a high capability for canceling ghosts in the frequency band in which the ghost canceling is required. The apparatus utilizes an error detector and a tap gain control in a closed loop to control the gain of a transversal filter. In addition, a frequency transfer characteristic modifier is utilized to modify the loop frequency transfer characteristics so as to optimize the cancelation of ghosts.

Ghost canceling apparatus

A TV tuner circuit having a dual-gate MES FET in a UHF RF amplifier and a dual-gate MOS FET in a VHF RF amplifier which are both controlled by a single AGC voltage source. The source of the MES FET is always connected to a DC source voltage input through a resistor so as to ensure that no DC current flows from an AG voltage source to the second gate of the dual-gate MPES FET in receiving VHF signals. Accordingly, there is no drop in the AGC voltage applied to the second gate of the dual-gate MOS FET in the VHF RF amplifier, thereby enabling both the UHF RF amplifier and the VHF RF amplifier to have the same gain reduction characteristics.

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Yokohama, Japan

Takeshi Sato