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公开(公告)号：JPH0662581A
公开(公告)日：1994-03-04
申请号：JP22927192
申请日：1992-08-05
Applicant: YAMAHA CORP
Inventor： NORO MASAO
IPC: H02M7/06 , H02M7/12 , H02M7/21 , H02M7/48 , H02M7/5387
Abstract: PURPOSE:To provide a power source circuit which reduces current noise with both input and output based on current continuous mode. CONSTITUTION:One end of an inductance L1 is connected to the positive side terminal 1 of a DC voltage source V1, and one end of an inductance L2 to the negative side terminal 2 of a DC voltage source V2. The other ends of the inductances L1, L2 are connected to an AC output terminal 3 via switching devices S1, S2 and diodes D1, D2, respectively. The diode D1 has an anode on the output side, and the diode D2 has a cathode on the output side, and a capacitor C is connected between the other ends of the inductance devices L1, L2. Excitation power and inertial current of the inductance devices by on-off of the switching devices are made to flow continuously with the capacitor used as their bypass route, so that current noise can be reduced.
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公开(公告)号：JPH0662571A
公开(公告)日：1994-03-04
申请号：JP22639492
申请日：1992-08-03
Applicant: YAMAHA CORP
Inventor： NORO MASAO
IPC: H02M3/28
Abstract: PURPOSE:To provide a switching power circuit having a switching snubber circuit which requires no complicated timing circuit. CONSTITUTION:A switching power circuit has a transformer T wherein a primary winding N1 is connected to a source of DC voltage source VIN through a switching element SW. A snubber circuit is constituted of a constant current circuit composed of a transistor Q which is driven by the constant voltage developed across a specific terminal of the transformer T and a resistor R inserted into an emitter of the transistor Q and a capacitor C for absorbing a voltage noise. The voltage noise absorbed by the capacitor C through a base collector junction of the transistor Q and the charging charge is regenerated to the transformer T through the transistor circuit and then the transistor Q is automatically turned off when the regenerative current is saturated.
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公开(公告)号：JPH061974B2
公开(公告)日：1994-01-05
申请号：JP7117088
申请日：1988-03-25
Applicant: YAMAHA CORP
Inventor： SUZUKI EIICHI , YOKOYAMA KENJI , NORO MASAO
Abstract: A DC-to-DC voltage-increasing power source suitable for use in an audio device mounted on an automobile or a portable type audio device includes a DC power source (40), a drive pulse generation circuit (42) for generating drive pulses which are in 180 degree phase relationship, a switching circuit (44) of a push-pull connection supplied with operating voltage from the DC power source and driven between an on-state and an off-state in response to the drive pulses, a charge and discharge circuit (46) including capacitors charged by being connected in parallel to the DC power source and discharging a sum voltage by being connected in series to the DC power source and an output takeout circuit (48) for taking out this sum voltage as a voltage-increasing DC output. The switching cirucuit (44) is constructed of voltage-controlled type elements whose on-state is changed in response to the level of an on-pulse in the drive pulses and the drive pulse generation circuit (42) includes a pulse level changing circuit for changing the level of the on-pulse. In one aspect of the invention, the switching circuit includes a variable time constant circuit for transmitting an on-pulse with a relatively large time constant and an off-pulse with a relatively small time constant.
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公开(公告)号：JPH05304772A
公开(公告)日：1993-11-16
申请号：JP13431192
申请日：1992-04-27
Applicant: YAMAHA CORP
Inventor： NORO MASAO
Abstract: PURPOSE:To provide a low-noise and high-efficiency power supply circuit using a switching inverter circuit. CONSTITUTION:A first inductance element L1 and a second inductance element L2 are inserted into an input terminal and a reference terminal, respectively, and then a current continuity mode DC-DC converter 21 is provided at a former stage and then a current voltage resonance type switching inverter circuit 24 is provided at a later stage, thus constituting a switching power supply circuit. The switching inverter circuit 24 uses an npn transistor Q6 as a switching element, a current resonance circuit and a voltage resonance circuit are constituted of a capacitor C4 and a leakage inductance of a transformer T and then a capacitor C5 and a primary coil winding P1 of the transformer T, respectively, and then a timing control circuit 27 is constituted of an inductance element L3 and a capacitor C7.
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公开(公告)号：JPH05176531A
公开(公告)日：1993-07-13
申请号：JP27314391
申请日：1991-09-25
Applicant: YAMAHA CORP
Inventor： NORO MASAO
Abstract: PURPOSE:To prevent a resonance frequency from differing among a plurality of outputs even when there is a difference in a leakage inductance among them, in the case when the leakage inductance of a transformer is used as an inductance for current resonance and a plurality of outputs are taken out from this transformer. CONSTITUTION:A DC power source 1 is switched by switching elements S1 and S2 alternately and impressed on a primary winding 20 of a transformer, voltages induced in a plurality of secondary windings are rectified and smoothed and thereby a plurality of outputs are obtained. The value of a leakage inductance between the primary and secondary sides of the transformer T1 differs for each of windings 11 to 13 (L1 to L3). When this inductance is used as an inductance for current resonance, capacitors C2a, C2b and C2c for the current resonance are disposed on the secondary side and values thereof are set appropriately. Thereby resonance frequencies in the windings 11 to 13 are made uniform.
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Patent Agency Ranking
公开(公告)号：JPH0564446A
公开(公告)日：1993-03-12
申请号：JP24835491
申请日：1991-09-02
Applicant: YAMAHA CORP
Inventor： NORO MASAO
Abstract: PURPOSE:To elevate entire conversion efficiency and reduce line noise, etc., by using a high-efficiency, low-noise, and inconstant-voltage type resonance power source for an AC/DC converter (bulk power source). CONSTITUTION:Since DC/DC converters 31-35 have constant voltage properties, there is no necessity of constant voltage function in a bulk power source (AC/DC converter 20). So, a resonance power source without constant voltage function is used for this bulk power source 20. This resonance power source is advantageous for isolation due to nonexistence of primary and secondary feedback, and also the switching is performed by complete zero cross, so it is of low noise and high efficiency. Furthermore, since single output will do, the resonance operation becomes more stable. Hereby, low noise promotion (line noise, radiant noise, etc.) and high efficiency promotion can be materialized.
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公开(公告)号：JPH0549249A
公开(公告)日：1993-02-26
申请号：JP22343591
申请日：1991-08-08
Applicant: YAMAHA CORP
Inventor： NORO MASAO
IPC: H02M3/28
Abstract: PURPOSE:To stabilize the output voltage with simple constitution and with the operation being stable even at light load. CONSTITUTION:A constant voltage circuit 16 is connected to the rear stage of a switching inverter circuit 10. The constant voltage circuit 16 is equipped with a nonswitching path 20 and a switching path 18. The transistor Q2 of the switching path 18 is switched with the voltage being gotten by taking out one part of the output of the circuit 10 and converting it into triangular waves with an integration circuit 22. With this, the circuit for switching is simplified. Since the peak level of the triangular wave is low at light load, the transistor Q2 is turned off, and power is supplied from the nonswitching path 20, and the use of the switching path 18 bad in the stability at light load is avoided. When the load becomes heavy, the voltage of a resistor R2 adds to a switching driving signal, and the transistor Q2 is switched, and power is supplied on the switching path 18.
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公开(公告)号：JPH04277934A
公开(公告)日：1992-10-02
申请号：JP6395891
申请日：1991-03-05
Applicant: YAMAHA CORP
Inventor： NORO MASAO
Abstract: PURPOSE:To effectively prevent the noise faults from being caused by the switching actions. CONSTITUTION:The signal received by an antenna 1 is amplified by a high frequency amplifier 2 and mixed with the output of a local. oscillator 4 into an intermediate wave IF signal by a mixing circuit 3. The IF signal is amplified by an intermediate amplifier 5. The output of the oscillator 4 is applied to a divider 6 and divided at an appropriate dividing into. The output of the divider 6 is applied to a switching power supply 7. The frequency obtained by dividing the local oscillation frequency of the oscillator 4 by the divider 6 is used as the switching frequency of the supply 7. Therefore the switching frequency changes in response to the local oscillation frequency corresponding to a received frequency. Thus the switching frequency is variably controlled in response to the received frequency and therefore the noise influences can be effectively reduced in all received frequency bands.
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公开(公告)号：JPH03196798A
公开(公告)日：1991-08-28
申请号：JP33521089
申请日：1989-12-26
Applicant: YAMAHA CORP
Inventor： YOKOYAMA KENJI , NORO MASAO
Abstract: PURPOSE:To constitute the driving device to be smaller than an exclusive driving device inexpensively by supplying energy by a normal device amount other than the electric energy by increased amount from a 1st power amplifier. CONSTITUTION:An amplifier unit executes a negative impedance drive to a speaker unit 2 by cooperating with a power amplifier. A negative resistance (-Rv) which erases an internal impedance Rv is generated independently by an acoustic device on a speaker 2 side, so the speaker 2 becomes a completely dead state, and is driven and controlled strongly. And, by adaptively setting the transmission function T(s) of transmission property imparting circuit 33, the output voltage of the power amplifier can be made small to increase power supply, and the compensation of the frequency can be executed.
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公开(公告)号：JPH0322798A
公开(公告)日：1991-01-31
申请号：JP15580089
申请日：1989-06-20
Applicant: YAMAHA CORP
Inventor： NORO MASAO
Abstract: PURPOSE:To attain a system-up at a low cost by driving a loudspeaker by changing a transfer characteristic of its power amplifier to a desired characteristic by combining it with a commercial power amplifier. CONSTITUTION:As for an adaptor 10, a first terminal 11 is connected to a signal source of a pre-amplifier or a line amplifier, etc., a second terminal 12 is connected to an input terminal 21 of a power amplifier 20, a third terminal 13 is connected to an output terminal 2 of the power amplifier 20, and also, a loudspeaker 3 is connected to a fourth terminal 14. Accordingly, a negative impedance generating circuit is constituted as a whole. In such a way, it will suffice that a user having a conventional power amplifier 20 purchases only the adaptor 10, and the system-up can be attained at a low cost.
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