JPS5831614A - Triangle wave oscillator - Google Patents

Abstract

PURPOSE:To set potentials of upper and lower limit of a triangle wave to a desired value, by performing charge/discharge of a capacitor and determining both said potentials with a potential given externally. CONSTITUTION:Three transistors(TR) with arranged characteristics, 1, 2 and 3 are connected for common emitter and grounded via a constant current circuit 12. An emitter of TRs 4, 5 and 6 with opposite polarity as the TRs 1, 2 and 3 is connected to each base of the TRs 1, 2 and 3. The base of the TR4 is connected to a charge/discharge terminal of a capacitor 15, the base of the TRs 5, 6 is connected to a voltage source having equal voltages as desired minimum and maximum charging voltages Vmin and Vmax of the capacitor 15 respectively. A short-circuiting circuit of the capacitor 15 consisting of TRs 7 and 8 is connected to the TR6. A switch 20 is provided to the capacitor 15, and the potential of the upper and lower limit of a triangle wave can be set to a desired value, by changing over the switch 20 to the discharge position at the Vmax and to the charging position at the Vmin.

Description

Detailed Description of the Invention The present invention sets the upper and lower limit potentials of the triangular wave to desired potentials by determining the upper and lower limit potentials of the triangular wave by externally applied potentials. The present invention provides a triangular wave oscillator that can perform

FIG. 1 is a circuit diagram showing the configuration of an embodiment of the present invention, in which 1 to 3 are NPN type transistors with the same characteristics, 4 to 7 are PNP type transistors, and 8 is an NP type transistor.
N-type transistors, 9 to 14 are constant current circuits, 15
is a capacitor, 16. 17 is a resistor; 18 is a high potential input terminal to which a high potential signal for setting the upper limit potential of the triangular wave is input; 19 is a low potential input terminal to which a low potential signal for setting the lower limit potential of the triangular wave is input; 20 is the transistor 7; Capacitor 1 with one end grounded according to the presence or absence of collector current
A switch composed of a semiconductor element switches the other end of 5 to terminal A or BK, 21 is an output terminal that outputs a triangular wave, and 22 is a power supply.
The emitters of transistors 1, 2 and 3 are connected to each other as shown in FIG.
and 6 (input stage transistor) by setting the input potential to the highest potential among the three potentials V, V- and V-, and the transistor 11 related to the highest potential.
A three-input circuit is constructed in which only one input is in a conductive state and the other two are in a non-conductive state. Next, at point a shown in the operation diagram of this embodiment configured as described above, This is a time chart showing the voltage, vrIMl!
and vrnin indicate the potentials of the signals input to the high potential input terminal 18 and the low potential input terminal 19, respectively. In addition, Fig. 2(b) to f) are respectively the first
3 is a time chart showing the current flowing through points 1 to 3 shown in the figure.

First, when switch 20 is connected to terminal B,
The capacitor 15 is charged by the constant current of the constant current circuit 9, and the potential V of the output terminal 21 rises as shown in FIG. 2(a)K. In this state, the transistor 3 is in a conductive state (Fig. 2(d)), and the emitter potential of the transistors 1 and 2 is higher than the pace potential, respectively, and the transistors 1 and 2 are in a conductive state (Fig. As shown in e), it is in a non-conducting state. Then, when the potential V of the output terminal 21 reaches the potential vrIIaX of the high potential input terminal 18, the transistor 1 becomes conductive mK. Therefore, a current flows to the collector of transistor 1, and transistors 7 and 8 become conductive (Fig. 2(e) and (f).
)), the transistor 3 becomes non-conductive as shown in FIG. 2(d), the switch 20 switches from the terminal 1B to the terminal A, and the capacitor 15 begins to discharge through the constant current circuit 10. As the discharge of the capacitor 515 progresses, the potential V of the output terminal 21 decreases as shown in FIG. During such a discharge period of capacitor 15, transistors 7 and 8 are in a conductive state, and therefore transistor 3 is in a non-conductive state. Then, when the potential V of the output terminal 21 falls and reaches the potential v2 of the low potential input terminal 19, the transistor 2
becomes conductive as shown in FIG. 2(e), and the transistor becomes non-conductive. For this reason, as shown in the first steps (e) and (f), iRangistaph and B become non-conductive, the switch 20 switches from terminal A to terminal B, and the capacitor 15 begins to charge.
Transistor 3 becomes conductive as shown in the second WJ(a)K, and transistor 2 becomes non-conductive (second
Figure (c)).

As described above, since the capacitor 15 is repeatedly charged and discharged, a triangular wave having an upper limit potential of -8 and a lower limit potential vmin as shown in FIG. 2(a) is output from the output terminal 21. In this embodiment, since the capacitor 15 is charged and discharged via the constant current circuits 9 and 10, the oscillation local wave number of the output triangular wave is proportional to vl-v2.

As described above, the present invention has the advantage that the upper and lower limit potentials of the triangular wave can be set to desired potentials by applying potentials from outside.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing the configuration of an embodiment of the present invention, and FIG. 2 is a time chart showing voltages or currents at each point shown in FIG. 1, 2.3.8......NPN type transistor, 4,5゜6.7......PNP
type transistor, 9 to 14,...
・Constant current circuit, 15... Capacitor,
16.17...Resistor, 18...
...High potential input terminal. 19...Low potential input terminal, 20...
・・・−・Switch, 21・・・・・・Output terminal, “mtLK・・・・・・High potential input terminal potential s ■min・・・・・・・・・Low Potential of potential input terminal, ■・・・・・・・・・ Potential of output terminal. Patent applicant Matsushita Electric Industrial Co., Ltd. Figure 1 Figure 2

Claims (2)

[Claims] (1) The first type with the same characteristics. The second and third three transistors of the same polarity are connected in parallel with each other and their emitters are commonly connected. At the bases of each of the second and third transistors, there is a fourth transistor having a polarity opposite to that of the first to third transistors. @ Connect the emitters of the 5th and 6th transistors, and connect the 1st emitter of the 4th to 6th transistors.
One base is connected to the charging/discharging side terminal of the capacitor which is charged and discharged through a switch, and each base of the other two transistors is connected to the desired minimum charging voltage vml of the capacitor. The seventh transistor is connected in such a way that the output circuit of this transistor is short-circuited when the capacitor K11i is discharged. 4. When the charging voltage of the capacitor reaches Vnax, the switch is switched to the discharging side.
0) The transistor is made conductive, and when the charging voltage of the capacitor reaches vmin, the switch is switched to the charging side and the seventh transistor is turned off, so that the output changes between vmln and vm&x. A triangular wave oscillator characterized by: (2) A triangular wave according to claim (1), characterized in that a constant current circuit is connected in series to each of the emitters of the first to sixth transistors and the charging circuit and discharging circuit of the capacitor. oscillator.