Title:
OSCILLATION DETECTING CIRCUIT
Document Type and Number:
Japanese Patent JP3937888
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To provide an oscillation detecting circuit which can detect stably oscillation of an oscillation circuit without being affected by an irregularity in transistor characteristic.
SOLUTION: Current sources IS11, IS12 are connected in series between a power source VDD and ground VSS. A capacitor C1 is connected with a connection point P1 of the current sources IS11 and IS12, and integrates a signal appearing at the connection point P1. A switch 1 is arranged between the current source IS11 having a large current value and the connection point P1. The integrated signal is input in a Schmitt trigger ST1, which outputs a binary signal. It is input in an AND circuit AN and a detection signal OSCSTP is output. When the switch SW1 turns on and off on the basis of an output signal NCKM of the oscillation circuit, a current I11 is supplied intermittently to the capacitor C1. As a result, a signal level of the connection point P1 rises and the detection signal OSCSTP turns to high level, so that oscillation is detected.
Inventors:
Yasuhiko Sekimoto
Application Number:
JP2002089332A
Publication Date:
June 27, 2007
Filing Date:
March 27, 2002
Export Citation:
Assignee:
Yamaha Corporation
International Classes:
H03K5/19; H03B1/00; H03K3/02; H03K4/02; H03L3/00; (IPC1-7): H03K5/19; H03K4/02
Domestic Patent References:
| JP10173637A | ||||
| JP1189223A | ||||
| JP2000332585A | ||||
| JP2001127248A | ||||
| JP52075130A | ||||
| JP57053142A | ||||
| JP57144592A | ||||
| JP2000224015A |
Attorney, Agent or Firm:
Masatake Shiga
Takashi Watanabe
Takashi Watanabe