EP0126325A2
Expired / Lapsed
EP
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Drive circuit for piezoelectric stack
Assignee: NEC Corp
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Filing: 1984-04-25
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Granted: —
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Expires: 2004-04-25
Abstract
Abstract A drive circuit for a piezoelectric stack which drives a desired mechanical object such as a printing head of a dot matrix printer or an ink jet printer. A winding is connected in series with one of electrodes of the pizoelectric stack so that an excitation voltage is applied to the stack via the winding. An excessive charge current at each time of drive and an excessive discharge current at each time of recovery are prevented.
Inventors
- 👤 Takeshi Yano
- 👤 Shinichi Hori
- 👤 Izumu Fukui
- 👤 Eiichi Sato
- 👤 Osamu Inui
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 21:04
CPC Classifications
H; H03; H03H; H03H9/00; H03H9/46; H03H9/54; H02; H02N; H02N2/00; H02N2/02; H02N2/06; H02N2/065; H02N2/067
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
89 words
A drive circuit for a piezoelectric stack, comprising: a piezoelectric stack connected to a reciprocating mechanical object and generating a dimensional strain in response to an excitation voltage applied across electrodes of said piezoelectric stack to drive said object in a reciprocating motion; a winding connected in series with one of said electrodes of said piezoelectric stack; and switch means for applying the excitation voltage to the piezoelectric stack via said winding in response to a drive signal which is representative of an application timing of the excitation voltage.
Claim 2
Dependent Claim
89 words
A drive circuit for a piezoelectric stack, comprising: a piezoelectric stack connected to a reciprocating mechanical object and generating a dimensional strain in response to an excitation voltage applied across electrodes of said piezoelectric stack to drive said object in a reciprocating motion; a winding connected in series with one of said electrodes of said piezoelectric stack; and switch means for applying the excitation voltage to the piezoelectric stack via said winding in response to a drive signal which is representative of an application timing of the excitation voltage.
Claim 3
Dependent Claim
45 words
A drive circuit as claimed in claim 1, in which the winding has an inductance which is predetermined such that a charge stored in the piezoelectric stack becomes substantially zero at a recovery time of oscillation of the dimensional strain generated in the piezoelectric stack.
Claim 4
Dependent Claim
30 words
A drive circuit as claimed in claim 1 or 2, in which the drive signal comprises a pulse having a duration which is substantially equal to a recovery time period,
Claim 5
Dependent Claim
57 words
an of 4. A drive circuit as claimed in any of claim 1 to 3, which the switch means comprises a transistor switch for applying the excitation voltage to the piezoelectric stack in response to the drive signal, and a diode for bypassing an excitation voltage which develops reversely to a forward direction of said transistor switch.
Claim 6
Dependent Claim
35 words
A drive circuit as claimed in any of claims 1 to 4, in which the piezoelecric stack is constructed to generate the dimensional strain by a stiffened piezoelectric effect in response to the excitation voltage.
Claim 7
Dependent Claim
44 words
A drive circuit as claimed in any of claimsl to 5, in which the object to which the piezoelectric stack is connected is constructed to cause a printing wire to reciprocate by transmitting the dimensional strain to said printing wire after multiplying the strain.
Claim 8
Dependent Claim
122 words
A drive circuit for a piezoelectric stack, comprising: a piezoelectric stack connected to a reciprocating mechanical object and generating a dimensional strain in response to an excitation voltage applied across electrodes of said piezoelectric stack to drive said object in a reciprocating motion; a winding connected in series with one of said electrodes of said piezoelectric stack; first switch means for applying the excitation voltage to the piezoelectric stack via said winding in response to a drive signal which is representative of an application timing of the excitation voltage; and second switch means for dissipating a charge stored in the piezoelectric stack via the winding in response to a damp signal which is representative of a damping timing for the dimensional strain.
Claim 9
Dependent Claim
122 words
A drive circuit for a piezoelectric stack, comprising: a piezoelectric stack connected to a reciprocating mechanical object and generating a dimensional strain in response to an excitation voltage applied across electrodes of said piezoelectric stack to drive said object in a reciprocating motion; a winding connected in series with one of said electrodes of said piezoelectric stack; first switch means for applying the excitation voltage to the piezoelectric stack via said winding in response to a drive signal which is representative of an application timing of the excitation voltage; and second switch means for dissipating a charge stored in the piezoelectric stack via the winding in response to a damp signal which is representative of a damping timing for the dimensional strain.
Claim 10
Dependent Claim
47 words
A drive circuit as claimed in claim 7, in which the winding has an inductance which is predetermined such that a charge stored in the piezoelectric stack becomes substantially zero at a recovery time of oscillation of the dimensional strain which develops in the piezoelectric stack. or8;
Claim 11
Dependent Claim
42 words
A drive circuit as claimed in claim 7 or 8, in which the drive signal comprises a pulse having a duration which is substantially equal to a recovery time period of oscillation of the dimensional strain which develops in the piezoelectric stack.
Claim 12
Dependent Claim
55 words
A drive circuit as claimed in any ofclaims 7 to 9, in which the first switch means comprises a transistor switch for applying the excitation voltage to the piezoelectric stack in response to the drive signal, and a diode for bypassing an excitation voltage which develops reversely to a forward direction of said transistor switch.
Claim 13
Dependent Claim
55 words
A drive cicuit as claimed in any of claims 7 to 10, in which the second switch comprises a transistor switch for dissipating the charge stored in the piezoelectric stack in response to the damp signal, and a diode for bypassing a discharge current which develops reversely to a forward direction of said transistor switch.
Claim 14
Dependent Claim
60 words
A drive circuit as claimed in any of claims 7 to 11, in which the second switch means has a resistor connected in series with the winding and is constructed such that the winding, the resistor and the piezoelectric element complete a serial closed path to danp the mechanical vibration of the piezoelectric stack when the damping timing is reached.
Claim 15
Dependent Claim
30 words
A drive circuit as claimed in claim 12, in which the resistor has a resistance which is predetermined to substantially satisfy a critical oscillation condition in the serial closed path.
Claim 16
Dependent Claim
35 words
A drive circuit as claimed in any of claims 7 to 13, in which one of the drive signal and the damp signal is produced by inverting high and low voltage levels of the other.
Claim 17
Dependent Claim
32 words
A drive circuit as claimed in any of claims 7 to 14, in which the piezoelectric stack generates the dimensional strain by a stiffened piezoelectric effect in response to the excitation voltage.
Claim 18
Dependent Claim
45 words
A drive circuit as claimed in any of claims 7 to 15, in which the object to which the piezoelectric stack is connected is constructed to cause a printing wire to reciprocate by transmitting the dimensional distortion to said printing wire after multiplying the strain.
References Cited (Backward Citations)
EP0048942A2
Cited
EP0099683A2
Cited
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