HA17339A_15 Datasheet, PDF (12/17 Pages) Renesas Technology Corp – Quadruple Comparators

HA17339A Series
2. Pulse Generator
The charge and discharge circuits in the circuit from figure 1 are separated by diodes in this circuit. (See figure 3.)
This allows the pulse width and the duty cycle to be set independently. Figure 4 shows the waveforms generated by
this circuit.
V_CC
R₁ 1M D₁ IS2076
R₂ 100k D₂ IS2076
C
−
V_CC
80pF
HA17339A
V_CC
+
1M
Vout
1M
1M
Figure 3 Pulse Generator
Horizontal: 2 V/div, Vertical: 20 µs/div, V_CC = 5 V Horizontal: 5 V/div, Vertical: 20 µs/div, V_CC = 15 V
Figure 4 Operating Waveforms
3. Voltage Controlled Oscillator
In the circuit in figure 5, comparator A₁ operates as an integrator, A₂ operates as a comparator with hysteresis, and
A₃ operates as the switch that controls the oscillator frequency. If the output Vout1 is at the low level, the A₃ output
will go to the low level and the A1 inverting input will become a lower level than the A1 noninverting input. The A1
output will integrate this state and its output will increase towards the high level. When the output of the integrator
A₁ exceeds the level on the comparator A₂ inverting input, A₂ inverts to the high level and both the output Vout1
and the A₃ output go to the high level. This causes the integrator to integrate a negative state, resulting in its output
decreasing towards the low level. Then, when the A₁ output level becomes lower than the level on the A₂
noninverting input, the output Vout1 is once again inverted to the low level. This operation generates a square wave
on Vout1 and a triangular wave on Vout2.
V_CC
V_CC
500p
100k
−
A₁
3k
5.1k
+V_C
10 _HA17339A
0.1µ
+
0.01µ
Frequency
control
20k
20k
V_CC/2
voltage
input
50k
V_CC
A₃
−
V_CC/2
V_CC = 30V
+250mV < +V_C < +50V
700Hz < / < 100kHz
HA17339A
+
100k
V_CC
+
A₂
HA17339A
−
V_CC
3k
Output 1
Output 2
Figure 5 Voltage Controlled Oscillator
Rev.3.00 Mar 10, 2006 page 10 of 14