JPS60235520A - Voltage converting and holding circuit - Google Patents

Abstract

PURPOSE:To observe sequentially the change in an input signal by applying charging with other charging means in response to an input signal while a comparator compares a voltage held in one charging means with a sawtooth wave and executing alternately the operation. CONSTITUTION:An emitter current Ie of a transistor TRQ1 flows with a prescribed peak value in response to the input pulse. When a control circuit 9 turns on a TRQ2 and turns off Q3, Q4, Q5, the current Ie charges a capacitor 5. When a time t0 is elapsed after start of charging, the TRQ3 is turned on and the Q2, Q4 and Q5 are turned off. The capacitor 5 holds a voltage just before the TRQ2 is turned off and the current Ie charges a capacitor 6 (section t1). A comparator 10 compares a V5 with an output voltage V11 of a sawtooth wave generating circuit 11 during this time. After the section t1 is elapsed, the TRQ4 is turned on, the Q2, Q3, Q5 are turned off, a voltage V6 is held so as to discharge the capacitor 5. When the voltage V5 reaches zero, the capacitor 5 is charged (section t'2) while the voltage V6 is held by turning on and off the Q2 and Q3, Q4, Q5. The V6 and V11 are compared. The operation above is repeated afterward, the input signal is observed without intermission so as to obtain a voltage to be compared.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a voltage conversion/holding system that converts an input signal into a voltage to be compared and holds it in order to compare a time-varying input signal with a set voltage using a comparator. Regarding circuits.

Conventional configuration and its problems For example, when comparing an input signal whose pulse width changes with time with a sawtooth wave voltage using a comparator, the input signal is charged to a charging means such as a capacitor for a certain period of time, and the voltage is It was common to obtain the voltage to be compared by holding the voltage. However, in such a voltage conversion/holding circuit, changes in the input signal during the time for comparison with the sawtooth wave voltage and the time for discharging the holding voltage of the charging means cannot be taken in as the voltage to be compared; There was a problem with poor responsiveness.

OBJECTS OF THE INVENTION In view of these conventional problems, an object of the present invention is to provide a voltage conversion/holding circuit that enables control with good response characteristics.

Structure of the Invention For this reason, the present invention provides a constant current circuit whose output current is controlled in accordance with a pulsed input signal, two charging means that are charged by the output of the constant current circuit, and a combination of the constant current circuit and the charging means. A changeover switch section interposed between the means, a discharging means for each charging means, and charging and discharging of the two charging means alternately, and while one charging means is charging and discharging, the other charging means is charged. It is equipped with a control circuit that controls the changeover switch section and the discharging means so as to maintain the voltage, and while the voltage held in one charging means is compared with the sawtooth wave in the comparator, the voltage held in the other charging means is To provide a voltage conversion/holding circuit in which charging is performed by means according to an input signal, and this operation is performed alternately so that changes in the input signal can be observed from time to time.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. 1st
In the figure, (1) is an input terminal to which a pulsed input signal is applied, and (2) is a constant current circuit, in which a constant current is obtained as the emitter current of the transistor (Q, 1) according to the pulse width of the input signal. It will be done. (3) and (4) are changeover switch sections, which are controlled by the signal from the control circuit (9) to
) and (Qs) are controlled to be on or off.

(5) and (6) are capacitors serving as charging means, and the output current of the constant current circuit (2) is connected to the changeover switch section (33).
This capacitor (5) or (6) is charged through (4). (7) and (8) are each capacitor (5) and (
A discharging means provided corresponding to 6) discharges the charged capacitor (5) or (6) by turning on the transistor (Q4) or (Q6) according to a signal from the control circuit (9). be. αQ is a comparator, (b) is a comparator α
Sawtooth wave generation circuit input to 1, (A) is comparator α0
A capacitor (5
) and (6), whichever has a higher voltage value is selected.

In Figure 2, v5 is the terminal voltage of the capacitor (5), v
6 indicates the terminal voltage of the capacitor (6), and V-th indicates the output voltage of the sawtooth wave generating circuit 01).

Next, the operation will be described. When a pulsed input signal is applied to the input terminal (1), the emitter current of the transistor (Ql) flows at a constant peak value according to the pulse width. Here, the transistor (Q
l) is on, transistor (Qs) (Q4XQ6)
is off, the emitter current flows through the capacitor (
5) Charge. At that time, the terminal voltage V8 of the capacitor (5) becomes as shown in the section to in FIG.

When to has elapsed after the start of charging the capacitor (5), the transistor (Qs) is turned on and the transistors (Q+) (Q4) (Qs) are turned off by a signal from the control circuit (9). At this time, the capacitor (5) is the transistor (
The emitter current of the constant current circuit (2) is controlled by the capacitor (6) 'i
Charging is complete. At this time, the terminal voltages 5 and V6 of capacitors (5) and (6) are in the state of section 11 in FIG.
During this time, comparator αQ outputs ■5 and sawtooth wave generation circuit α.
The output voltage Vl+ of η is compared. After the voltage rise period 1+ of this sawtooth wave has elapsed, the transistor (Q4) is turned on by the signal from the control device (9), and the transistor (Ql) (
Qs (Qs) is controlled to the off state, and the capacitor (6)
The terminal voltage of is held and the capacitor (5) is discharged. Condensed? (51) When the terminal voltage becomes 0, the transistor (Ql) is in the on state, and the transistor (Qs) (Q
4) (Qb) is turned off, and the capacitor (5) is charged while the terminal voltage of the capacitor (6) is maintained. This period is section t2 in FIG. Among these, in the sawtooth wave voltage rise section t2, v6, v, and l are connected to the comparator (]
Compare by 0. Thereafter, by repeating the same operation, the input signal can be observed seamlessly and the voltage to be compared can be obtained.

Although an example has been shown in which the output of the voltage conversion and holding circuit is input to the comparator αO, it is not necessarily a comparator, and other control circuits may be used. Similarly, since the voltage to be compared is not limited to the sawtooth wave, the charging/discharging timing of the charging means may be set using other control signals. In short,
Any configuration may be used as long as the two charging means are alternately charged and discharged alternately by a constant current circuit so that the voltage of any one of the charging means is maintained.

Effects of the Invention According to the voltage conversion/holding circuit of the present invention, as is clear from the above explanation, since one of the two charging means is always charged according to the input signal, it is not necessary to use one charging means. The response characteristics of the control device are better than those of conventional models, and accurate control can be performed.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of a simple embodiment of the present invention, and FIG. 2 is a voltage timing chart of the main parts. (1)...Input terminal, (2)...Constant current circuit, (3
3 (4)... Selector switch section, (5) (0)...
Capacitor (charging means), (7) (8)... discharging means, (9)... control circuit. Figure 7

Claims (1)

[Claims] A constant current circuit whose output current is controlled according to a pulsed input signal, and a 2-channel battery that is charged by the output of this constant current circuit.
a changeover switch section interposed between the constant current circuit and the charging means; a discharging means for each charging means; and a charging and discharging means for the two charging means alternately and one charging means for charging and discharging the two charging means. A voltage conversion and holding circuit comprising the changeover switch section and a control circuit that controls the discharging means so that the other charging means maintains the charged voltage during discharging.