Title:
自動調整発振器及びそれを用いたスイッチング電源
Document Type and Number:
Japanese Patent JP6812133
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To provide an automatic adjustment oscillator for automatically adjusting an oscillation frequency in a case where the oscillation frequency is shifted by variation in properties of circuit elements such as a resistor and a capacitor and a change of an ambient temperature or the like.SOLUTION: In accordance with increase/decrease of an oscillation frequency fosc of a sawtooth wave Vsaw outputted from an oscillator 10, a smoothing voltage V20 outputted from an F-V conversion circuit 20 is increased/decreased. A window comparator 30 outputs a high-level comparator output signal V30 to a first terminal of an up/down counter UD and outputs a low-level signal V31 to a second terminal. Thus, the up/down counter UD increases or decreases a stored count value by one. Output of the up/down counter UD is supplied to a decoder DEC. The decoder DEC adjusts a current Iosc by adjusting a combined resistance value of a ladder resistor circuit 40 and adjusts the oscillation frequency fosc of the sawtooth wave Vsaw generated in the oscillator 10 into an oscillation frequency within an allowable range.SELECTED DRAWING: Figure 1
Inventors:
Shingo Matsumaru
Yoshinori Sato
Yoshinori Sato
Application Number:
JP2016091076A
Publication Date:
January 13, 2021
Filing Date:
April 28, 2016
Export Citation:
Assignee:
ROHM Co., Ltd.
International Classes:
H03K3/02; H02M3/155; H03K4/06; H03K4/08; H03L7/06
Domestic Patent References:
| JP2007124394A | ||||
| JP2010206650A | ||||
| JP2005167927A | ||||
| JP20143804A | ||||
| JP2010258625A | ||||
| JP2004327116A |
Attorney, Agent or Firm:
Sano patent office