US3883754A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Frequency-voltage converter circuit, particularly for automotive applications
Assignee: Robert Bosch GmbH
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Filing: 1974-02-07
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Granted: 1975-05-13
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Expires: 1994-02-07
Abstract
Abstract A simple frequency-voltage converter circuit, particularly suitable for vehicle wheel brake anti-lock systems in which a voltage is derived representative of a wheel speed, from a tachometer generator, including a track-and-hold circuit in which a first charging capacitor is charged to a fixed value upon occurrence of the trailing flank of a pulse from the tachometer generator, and discharged during the pulse gap, and a charge transfer and comparator stage is connected thereto, including a second storage capacitor on which a charge is developed representative of the charge on a charging capacitor. The transfer and comparator stage includes an operational amplifier, connected to a charge diode, and a discharge diode, respectively, and rendering the charge and discharge diodes selectively conductive, the state of the storage and comparison capacitor being fed back to the input of the operational amplifier to effect comparison and hence control of the respective charge or discharge diode.
Inventors
- 👤 Helmut Fleischer
- 👤 Eberhard Schnaibel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 22:00
CPC Classifications
H; H03; H03K; H03K9/00; H03K9/06
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
139 words
Frequency-voltage converter circuit having a monostable flipflop (FF) (10) to which a signal of varying frequency is applied; charge storage means (159) connected to the monostable FF (10) to be charged upon change of state thereof; a function generator (15) controlling the discharge of said charge storage means and providing for a hyperbolic discharge rate thereof; a storage capacitor (257) and a charge transfer circuit therefor, the charge storage capacitor being charged to a value representative of the charge, or remaining charge, of the charge storage means, after discharge through the function generator; wherein the improvement comprises an operational amplifier (252) forming part of the charge transfer circuit (25), and a discharge circuit for the storage capacitor (257) including a discharge diode (254), said discharge circuit being connected to and controlled by the output of the operational amplifier (252).
Claim 2
Dependent Claim
139 words
Frequency-voltage converter circuit having a monostable flipflop (FF) (10) to which a signal of varying frequency is applied; charge storage means (159) connected to the monostable FF (10) to be charged upon change of state thereof; a function generator (15) controlling the discharge of said charge storage means and providing for a hyperbolic discharge rate thereof; a storage capacitor (257) and a charge transfer circuit therefor, the charge storage capacitor being charged to a value representative of the charge, or remaining charge, of the charge storage means, after discharge through the function generator; wherein the improvement comprises an operational amplifier (252) forming part of the charge transfer circuit (25), and a discharge circuit for the storage capacitor (257) including a discharge diode (254), said discharge circuit being connected to and controlled by the output of the operational amplifier (252).
Claim 3
Dependent Claim
59 words
Circuit according to claim 1, comprising means (261, 262, 259) including resistance means connecting the output of the operational amplifier (252) to a source of supply (30, 31); and a diode (256) connecting the output of the operational amplifier to the storage capacitor (257) and to the source of supply to form a charging circuit for said storage capacitor.
Claim 4
Dependent Claim
27 words
Circuit according to claim 2, wherein the means connecting the output of the operational amplifier (252) to the source of supply (30) comprises diode means (261, 262).
Claim 5
Dependent Claim
24 words
Circuit according to claim 1, further comprising resistance means (253) interconnected between the output of the operational amplifier (252) and the discharge diode (254).
Claim 6
Dependent Claim
80 words
Circuit according to claim 1, wherein the operational amplifier (252) is connected to be voltage-sensitive and connected in a comparison circuit to compare the voltage on the charge storage means (159) and the voltage appearing at the output (270) of the converter circuit, said operational amplifier means beIng connected to and controlling discharge of the storage capacitor (257) when the voltage on the charge storage means (159) is less than the voltage at the output (270) of the converter circuit.
Claim 7
Dependent Claim
73 words
Circuit according to claim 1, further comprising diode means (263) connected between the inverting input of the operational amplifier (252) and the output of the operational amplifier; a de-coupling transistor circuit (255, 256), including at least one transistor (255), the base of the de-coupling transistor (255) being connected to the discharge diode (254), and an output electrode (emitter) of the transistor being coupled (264) to the inverting input of the operational amplifier (252).
Claim 8
Dependent Claim
45 words
Circuit according to claim 1, further comprising connection means (103) connecting the input signal (101) to the function generator (20) and to the charge transfer and comparator circuit (25) to control operation of the operational amplifier in accordance with the state of the input signal.
Claim 9
Dependent Claim
39 words
Circuit according to claim 3, further comprising connection means (103) connecting the input signal to the diode means (261, 262) and to the resistance means (259) to control the timing of charging and discharging of the storage capacitor (257).
Claim 10
Dependent Claim
44 words
Circuit according to claim 1, wherein the function generator comprises a resistance-diode network; and a compensating coupling diode (266) is provided connected to the output (270) of the converter circuit to compensate for temperature variations of the diodes in the function generator diode network.
Claim 11
Dependent Claim
47 words
Circuit according to claim 1, wherein the monostable FF (10) has an output circuit including a voltage divider (111, 113, 114), the output from the monostable FF being taken from the tap or junction point (114) of the voltage divider and connected to the charging capacitor (159).
Claim 12
Dependent Claim
101 words
Circuit according to claim 10, further comprising a charge supply capacitor (158) having a capacitance which is high with respect to the capacitance of the charging capacitor (159); a controlled switch (153), the controlled switch being controlled from the monostable FF (10) and, selectively, connecting the charging capacitor (159) to be charged by charge stored on said capacitor (158) of large capacitance, and to isolate the charging capacitor (159) from said charge supply capacitor (158) and permit discharge through said function generator (20) and control of the charge transfer circuit (25) and hence the charge state on the storage capacitor (257).
Claim 13
Dependent Claim
97 words
Circuit according to claim 2, wherein the operational amplifier is connected to have a signal applied to one input thereof representative of the charge on the charging capacitor (159) and a signal applied to the other input thereof representative of the charge on the storage capacitor (257), said operational amplifier comparing said respective signals and providing an output which controls conduction of said discharge diode (254) or said charge diode (256), respectively, to provide a charge on the storage capacitor which will be representative of the charge on the charging capacitor (159) and to null any differences.
Claim 14
Dependent Claim
78 words
Circuit according to claim 12, wherein the discharge diode (254) is directly connected to the output of the operational amplifier to be controlled to be conductive thereby; and at least two serially connected diodes (261, 262) connecting the charge diode (256) to the output of the operational amplifier to provide different intrinsic voltage drops between the charge circuit including the charge diode (256) and the discharge circuit including the discharge diode (254) to provide for a control range.
Claim 15
Dependent Claim
105 words
Circuit according to claim 12, further comprising a negative feedback circuit (264, 263) between the output (270) of the converter circuit and the operational amplifier (252), said negative feedback circuit including a diode (263) to apply the negative feedback to the operational amplifier only when the charge diode (256) effects charging of the storage capacitor (257) to provide for rapid discharge of the storage capacitor (254) when controlled and commanded to discharge by the operational amplifier, but slower charge of the storage capacitor (257) when commanded and controlled by the charge diode (256) and upon application of said negative feedback through the negative feedback circuit.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-05-12 | 1978-11-11 | 1979-05-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-05-12 | 1982-11-11 | 1983-05-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-05-12 | 1986-11-11 | 1987-05-13 | $7700.00 | Window Closed / Lapsed |