公开(公告)号：JP2001345700A

公开(公告)日：2001-12-14

申请号：JP2000160896

申请日：2000-05-30

Applicant: YAMAHA CORP

Inventor： NORO MASAO

IPC: H03M1/12 ,  H03M1/48 ,  H03M3/02

Abstract: PROBLEM TO BE SOLVED: To provide an analog-to-digital converter circuit having high performance for audio use. SOLUTION: The analog-to-digital converter comprises an analog-to-digital converter 10 for converting digital signals of a plurality of bits into an analog signal, a comparator 12 inputting an input analog signal and an output signal of a digital integrator 14 to compare the input signal with an analog output signal of the converter 10 and to output 1-bit data responsive to a compared result, and the digital integrator 14 inputting the 1-bit data output from the comparator 12 to digitally integrate and to output a digital signal of a plurality of bits.

公开(公告)号：JP2001291261A

公开(公告)日：2001-10-19

申请号：JP2001022722

申请日：2001-01-31

Applicant: YAMAHA CORP

Inventor： MORISHIMA MORIHITO ,  HONDA KAZUHIKO ,  NORO MASAO ,  TSUJI NOBUAKI

IPC: G11B7/0045 ,  G11B7/125

Abstract: PROBLEM TO BE SOLVED: To realize a high-speed optical disk writing device. SOLUTION: The optical disk writing device comprises a main sheet 100, a pickup 200 and a flexible substrate 150 for connecting both. Since the flexible substrate 150 has a poor frequency characteristic, the pickup 200 is internally provided with a write strategy circuit 224, etc., for correcting the frequency characteristic in order to raise the level of the rising part of the signal transmitted in the flexible substrate 150 and to lower the level of the falling part. Arrangement is made to consume the current not consumed in a laser diode 300 by a current source and current consumption circuit 122 in the main sheet 100 in order to suppress the calorific value of the pickup 200.

公开(公告)号：JPH10107564A

公开(公告)日：1998-04-24

申请号：JP25902196

申请日：1996-09-30

Applicant: YAMAHA CORP

Inventor： MORITA KUNIAKI ,  NORO MASAO

IPC: H03G3/12 ,  G10H1/08 ,  H03G3/00

Abstract: PROBLEM TO BE SOLVED: To provide a mixer circuit that mixes a plurality of signals with a high S/N in a simple configuration without distorting the waveform. SOLUTION: Upon the receipt of inpvut signals V1-V5, they are mixed in response to ratios R1-R5 and the mixed signal is fed to a noninverting input terminal of a 1st operational amplifier OP1. The 1st operational amplifier OP1 acts like a noninverter amplifier, and a 2nd operational amplifier OP2 acts like an inverter amplifier. The gain of the 2nd operational amplifier OP2 is controlled through the selection of switches SWa-SWe. Thus, a level of an inverted output signal Vout is adjusted and the result is added to the input. In this case, since two of the SWa-SWe are closed simultaneously, the level is adjusted in detail without distorting the output signal Vout.

公开(公告)号：JPH08222972A

公开(公告)日：1996-08-30

申请号：JP4790395

申请日：1995-02-14

Applicant: YAMAHA CORP

Inventor： NORO MASAO

IPC: H03F3/45 ,  H03F3/30 ,  H03F3/343

Abstract: PURPOSE: To make an output of a push-pull operational amplifier circuit stable. CONSTITUTION: An input signal is fed to transistors(TRs) Q1, Q2 from input terminals 42, 44 respectively, an output of the TR Q2 is given to a gate of a TR Q13, and an output is extracted from a drain of the TR Q13. An output of a TR Q1 is given to a gate of a TR Q10, and an output of the TR Q10 is synthesized with an output by a current mirror circuit comprising TR Q11, TR Q12, and the TR Q13, TR Q12 are in push-pull operation. TR Q8, TR Q9 in an in-phase feedback stabilizing circuit 42 are driven by outputs of the TR Q1, TR Q2 and a sum IQ8 +IQ9 of currents IQ8 , IQ9 flowing to the TR Q8, TR Q9 flows to a TR Q7. The current IQ7 flowing to the TR Q7 is transferred to the TR Q6 by means of current mirror and respectively transferred to the TR Q3, TR Q4 by a TR Q5 by means of current mirror. Currents IQ19 , IQ13 of the TR Q10, TR Q13 driven by the same gate voltage as that of the TR Q8, TR Q9 are made stable by the operation of the in-phase feedback stabilizing circuit 42, and a current IQ12 is made stable, resulting that an output current IOUT is made stable.

公开(公告)号：JP2500553B2

公开(公告)日：1996-05-29

申请号：JP24835491

申请日：1991-09-02

Applicant: YAMAHA CORP

Inventor： NORO MASAO

IPC: H02M3/28 ,  H02M3/335 ,  H02M7/48

公开(公告)号：JPH06189544A

公开(公告)日：1994-07-08

申请号：JP35456092

申请日：1992-12-16

Applicant: YAMAHA CORP

Inventor： NORO MASAO

IPC: H02M3/335 ,  H02M7/5387

Abstract: PURPOSE:To provide a two-transistor type switching power supply circuit for driving two switching elements with a simplified constitution. CONSTITUTION:A bridge type switching circuit is constituted by two diodes D1, D2 and two switching elements SW1, SW2 and a power is supplied to a transformer T through ON-OFF drive of the switching elements SW1, SW2. The first switching element SW1 is provided with a switching element drive circuit 1 for controlling the ON/OFF of the element itself in the predetermined period, while the secondary switching element SW2 receives directly a voltage across a sub-coil P2 of the transformer T as a drive voltage.

公开(公告)号：JPH05304774A

公开(公告)日：1993-11-16

申请号：JP13431392

申请日：1992-04-27

Applicant: YAMAHA CORP

Inventor： NORO MASAO

IPC: H02M3/28 ,  H02M7/06 ,  H02M7/537

Abstract: PURPOSE:To provide a low-noise and high-efficiency synchronization-type switching power supply where a switching regulator and a switching inverter are combined. CONSTITUTION:A switching regulator 11 is provided at a former stage and a switching converter circuit and an output circuit 15 for taking out the output after rectification and smoothing are provided at a later stage. The switching converter circuit is provided with a switching means 12, a voltage resonance circuit 13, a current resonance circuit 14, and a timing control means 18 for turning on or off the switching means and then the switching regulator 11 is provided with a starting circuit 16 for automatically starting it when an input voltage is given and for automatically stopping functions when the switching inverter circuit at the later stage starts operation. The switching regulator 11 is controlled stably at a constant frequency by a PWM circuit 17 in synchronization with the switching inverter circuit at the later stage when it starts operation.

公开(公告)号：JPH0542165B2

公开(公告)日：1993-06-25

申请号：JP13338988

申请日：1988-05-31

Applicant: YAMAHA CORP

Inventor： NORO MASAO

IPC: H04R3/04 ,  H03F1/30 ,  H03F1/34 ,  H03F1/38 ,  H04R3/00

公开(公告)号：JPH0564366A

公开(公告)日：1993-03-12

申请号：JP25302091

申请日：1991-09-04

Applicant: YAMAHA CORP

Inventor： NORO MASAO

IPC: H02J1/10 ,  H02M3/155

Abstract: PURPOSE:To provide a power device which supplies to additionally installed boards, etc., the power of the output of a power source or more by effectively using the output of the power source of a main body of an equipment or more and which does not cause the malfunction of the main body of the equipment, the additionally installed boards, etc. CONSTITUTION:Between the body of an equipment 1 and the load 2, an auxiliary power supply section 3 is installed. On a power line P drawn from a main power supply 11 to the load 2, a current detector 12 is installed, whose output is amplified by an amplifier 13. The output of the amplifier 13 is sent to a PWM control circuit 14. A PWM signal output from the PWM control circuit 14 is sent to a base of a switching transistor 15. An emitter of the switching transistor 15 is connected to the power line P through an auxiliary power supply 16. A collector of the switching transistor 15 is connected to the power line P through a coil 17 while being connected to a power line N through a diode 18.

公开(公告)号：JPH04364362A

公开(公告)日：1992-12-16

申请号：JP16638391

申请日：1991-06-11

Applicant: YAMAHA CORP

Inventor： NORO MASAO

IPC: H02M3/28 ,  H02M3/335 ,  H02M3/337 ,  H02M3/338

Abstract: PURPOSE:To improve efficiency by performing all switching operations with zero voltage or zero current, making use of current and voltage resonance operations alternately, and to reduce the harmonic components of the operation voltage and current waves inside a circuit. CONSTITUTION:When the first switch 1 is turned on, a resonance current in the shape of sine waves flows to resonance means L2 and C2 in series, and the smoothing capacitors C3 and C4 of DC output means are charged. Since the current seeks to be inverted when the resonance circuit passes by a half wave, rectification diodes D1 and D2 are biased reversely, and the resonance path is cut off, and the resonance current vanishes automatically During the on period of the first switching element, L1 excitation and C1 charge accumulation are performed, while resonance is being performed in parallel resonance means L1 and C1. During the zero current period after that, the first switching element is turned off. At the same time, the resonance operation of the parallel resonance means is started, and the output end voltage of the switching means is changed from one voltage to the other voltage, making use of the voltage resonance wave in the shape of sine waves. And while the output end voltage of the switching means is near the other potential, the second switching element is turned on. The first and second elements repeat the above operation.