DE3323039A1 - Pulse duration/voltage converter - Google Patents

Abstract

A pulse duration/voltage converter is proposed which consists of an integrating device, the output value of which can be set to a certain value before conversion and can be stored after conversion. This makes it possible to carry out pulse duration/voltage conversions in direct succession, the voltage value corresponding to the pulse duration and stored being available for further processing until the end of the next conversion. <IMAGE>

Description

3323539. ::. :

^R ; IQ / Ö

3-1 .5. 1983 Sr / Hm

ROBERT BOSCH GMBH, TOOO STUTTGART 1

Pulse duration voltage converter
State of the art

The invention is based on a converter according to the preamble of the main claim. The output voltage of an operational amplifier (OV) connected as a reverse integrator is
a function of the input voltage of the OV, the initial value of the output voltage of the OV, the components of the circuitry of the OV that determine the integration time and the length of time that the input voltage is applied to the OV. Be: it is not possible for such an inverse integrator to
To set the initial value of the output voltage of the OVs to a certain, selectable value, it is also not- ■ possible to save the output voltage of the OVs.

Advantages of the invention

The converter according to the invention with the features of the main claim has the advantage that the output voltage of the operational amplifier (OV) can be set to a specific, selectable value, and that this 'The output voltage of the OV can also be saved. Furthermore, the OV is wired in such a way that no reverse integration takes place. It is also possible to operate the converter according to the invention in multiplex mode.

The measures listed in the subclaims are advantageous developments and improvements of the The converter specified in the main claim is possible.

drawing

Embodiments of the invention are shown in the drawing • and in more detail in the following description • explained. FIG. 1 shows the circuit diagram of a pulse duration-voltage converter FIG. 2 shows the time diagram of the pulse duration-voltage converter and FIG. 3 shows the pulse duration-voltage converter in multiplex operation.

Description of the exemplary embodiments

Figure 1 shows the circuit diagram of the pulse duration-voltage converter 10. The circuit consists of an "operational amplifier" (OV) 11, the resistors R1 12, R2 13 and R3 1 ^, the capacitors C1 15 and C2 16, the switches

S _x 1T ₅ S _n 18 and S _c 19 and the two pulse generation-In b '

■ sin direction η 20 and 21.

The inverting input of the OV is led through the resistor Ri and the switch S to ground. The inverting input of the OV is also connected to the output of the OV via the capacitance C1, whereby the capacitance Cl can be bridged _{by the switch S n.} The non-inverting input of the OV is connected to the battery voltage LL via the resistor R2 and to ground via the resistor R3; The output of the OV is connected to _{ground via the switch S Q} and the capacitance C2.

The switch S _T is controlled by the pulse I to be converted, which is provided by the pulse generating device 20. The switch S _R is used to reset and the switch S_ to store the output voltage U. of the OV. The two switches are activated by the pulse generating device 21 with the pulses R and S, respectively.

The voltage U. is the "output voltage" of the OV, the voltage U is at the Wii
on-the capacitance C2 on.

Voltage U is across resistor R3 and the voltage

The subject matter of FIG. 1 is expediently explained with the aid of the timing diagram from FIG. 2. With R there are the reset pulses which control _{switch S 13}

shown, with S the storage pulses controlling the switches S_ and with I _{the pulses controlling the switch S T} which are to be converted into a voltage. The 'designation T _T indicates the duration of the first pulse which controls the switch S_ and which is to be converted into a voltage by the pulse duration-voltage converter. The voltage U. is the output voltage of the OV, where U is the initial value

represents this output voltage. With U is the voltage referred to, which is applied to the capacitance C2.

If all three switches S _T , S ₁₅ and S_ are open, the voltages U. and U _{c are} not defined. The voltage U ", however, has the value U = U _ / (1 + R2 / R3). If the switching

O £ 5

tar S ₁ , triggered by a reset pulse, then n remains

the voltage U continues to be undefined. The voltage U, however, assumes the value U = U. While the pulse to be converted _{closes the switch S T} , the output voltage U. of the OV increases according to the puncture U. (t) = U (i + t / R1.Ci)

A * AO

After the pulse duration to be converted with the length .T ₁ . the output voltage U. of the OV remains at the value

χ A

U- (T) = U (1 + T -. / R1.C1) stand. The voltage U _c is still undefined at this time. Only by the driving of the switch S _g by a latch pulse, the capacitor C2 to the value U '= U. (T_) is charged, then, if a second pulse duration-voltage Wandlüng initiated by a reset pulse to the switch S _R, so does the Voltage U. back to its initial value U = U

A. Ά. Ο

on, but the voltage U- retains the voltage value of the first converted pulse duration U = U. (T_). A new voltage value U- is only stored on capacitance C2 by the next storage _{pulse on switch S g.}

The voltage U can be set to a certain value by choosing the resistors R2 and R3, The rise time of the output voltage U. of the OV can be given a certain value by choosing the resistor R1 and the capacitance C1.

FIG. 3a shows a circuit structure for the multiplex operation of the pulse duration-voltage converter. The structure consists of the pulse duration voltage converter 10,

, 10 / y

the "two pulse generating devices 20 and 21, one .Data generating device 22, a switching device 23 and the storage capacities C21 2U and C22 25.

The. Switching device 23 is with the pulse duration voltage r converter 10 connected. The storage capacities are at the outputs of the switching device C21 and C22 connected, the second connection of which is grounded. . ■

The pulse duration voltage converter 10 is from the pulses I, R and S driven, which are supplied from the pulse generating devices 20 and 21. The switching device 23 is connected to data lines, which are supplied by the data generating device .22 with data D-1 Dn are applied.

The voltage U _n - is the voltage across the storage capacitor C21, the voltage U _po is across the capacitor C22

at. ■ "■ -.-

The switching device consists 'essentially of' ;; a selector switch that controls the 'connection of the pulse duration' Voltage converter to one of the following storage capacities manufactures. The selection and switching to one of these storage capacities is thereby controlled by the data D1 ... Dn.

In the shown in Figure 3b to be converted pulses zB.die pulse duration "T_ _Λ in a voltage U _n" I will now be converted, which is stored on the capacitance C21, the pulse duration of T results in a voltage U, "which at the. Storage capacity C _?? is applied. '

By activating the selector switch of the switching device .that is, the storage of a converted pulse duration on a certain capacity can be achieved.

The storage capacities used in the exemplary embodiments can also be replaced by other components or circuits that carry a voltage over a longer period of time Can save time.

Die.im embodiment of the pulse duration-voltage converter The circuitry shown for the operational amplifier can also be replaced by other circuits which also fulfill the integrating function of the operational amplifier circuit.

It is also possible to set the voltage U and the rise time to make the output voltage U. variable by using variable resistors. Through this operating parameters, e.g. temperature, can be set using a temperature-dependent resistor R1 or R2 in the circuit of the pulse duration voltage converter must be included.

Read the principle of a pulse duration voltage presented here. Conversion is not limited to an analog structure, but can also be implemented using digital component groups will.

J.

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Claims (1)

κ. 18 762 31 ". 5th 1983 Sr / Hm ROBEET BOSCH GMBH, 7000 STUTTGART 1 Expectations Ij Λ pulse duration voltage converter with an integrating Device, characterized in that the output value of the integrating device occurs before each conversion a certain, selectable initial value is set, and that after each conversion the output value of the integrating device is stored. 2. pulse duration voltage converter according to claim 1, characterized characterized in that the initial value of the integrating Device is generated by bridging the integrating device. 3, pulse duration voltage converter according to claim 2, characterized characterized in that the bridging of the integrating device is generated by means of a switching element that of a reset pulse that is directly or indirectly dependent on the pulse duration to be converted is controlled. it-. Pulse duration voltage converter according to at least one of Claims 1 to 3, characterized in that
the storage of the output value of the integrating device is brought about by means of a switching element which is controlled by a storage pulse which is directly or indirectly dependent on the pulse duration to be converted. 18762 5 · Pulse duration voltage converter according to at least one of Claims 1 "to U, characterized in that the output value of the integrating device is stored by means of a capacitance. 6. pulse duration-voltage converter according to at least one • of claims 1 to 5, characterized in that the pulse duration to be converted controls a switching element which is connected to the input of the integrating device. . . " 7. pulse duration-voltage converter according to at least one of the claims. 1 to "6, characterized in that the voltages of different converted pulse durations with the help of a switching device to different ones Memory can be saved. δ. Pulse duration voltage converter after at least one of 'Claims 1 to 7', characterized in that the integrating device consists of an integrator • tes.chwitched operational amplifier exists, its non-inverting Input is at a constant voltage, des.sen inverting input by means of a Switch (.-17) with the pulse duration to be converted ' whose output voltage is set to an initial value by means of a switch (18) and the output of which is connected to a capacitor (16) via a switch (19), and that the two switches (■ 18, 19) can be switched depending on the pulse duration to be converted.