3A OUTPUT PROGRAMMABLE
POWER OSCILLATOR
TC96C555
TYPICAL CHARACTERISTICS
(Cont.)
ROUT vs. Temperature
Output HIGH
10
7
6
8
5
1
ROUT vs. Temperature
Output LOW
2
3
ROUT (Ohm)
6
5V
ROUT (Ohm)
4
5V
4
10V
3
2
10V
2
18V
VIN = 0V
1
18V
VIN = 3V
0
–55 –35 –15
5
25
45
65
85
105 125
0
–55 –35 –15
5
25
45
65
85
105 125
Temperature (°C)
Temperature (°C)
APPLICATIONS
The oscillator timing can easily be controlled by two
external resistors, R
CHG
and R
DIS
, and capacitor C. R
CHG
and R
DIS
set the two constant current sources for charging
and discharging C. The source current is always flowing
when in operation. When the capacitor has charged to a 2V
threshold, the current sink circuit is enabled to discharge the
VDD = 18V
+5V
TEST CIRCUIT
8
VREF
4
2
INPUT
6
1
GND
100KHz Square Wave
tRISE = tFALL
≤
10nsec
5
C1 = 1800pF
TC96C555
7
OUTPUT
OUTPUT
0V
10%
10%
18V
90%
1µF
WIMA
MKS-2
0.1µF
CERAMIC
INPUT
10%
0V
tD1
tD2
capacitor to the 1V threshold. When 1V is reached, the
current sink turns OFF to start another cycle.
Resistor R
CHG
is connected from V
REF
at Pin 3 to V
R1
Pin
4 to program the charging current. Current is set with resistor
R
DIS
connected from V
REF
Pin 3 to V
R2
Pin 1. Both currents
can range from 5µA to 150µA.
4
5
90%
3
tF
tR
90%
Figure 1. Output Switching Time
VDD
8
3
RCHG
4
VR1
RDIS
2
VIN
C
Q3
1
VR2
ISINK
2V
1V
6
Q2
GND
1V 2V 3V
ISOURCE
Q1
7
OUTPUT
VREF
4V
VREF
10µF
6
7
TCHG
2V
VIN
1V
VDD
OUTPUT
0V
5
Figure 2. Fixed Frequency Power Oscillator
Figure 3. V
IN
and Output Waveform
4-165
8
TELCOM SEMICONDUCTOR, INC.
TELCOM [ TELCOM SEMICONDUCTOR, INC ]
