TDA 4700
TDA 4718
Pin Definitions and Functions (TDA 4718)
Pin
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
Symbol
GND
Function
Ground 0 V
Ramp generator
R
R
Ramp generator
C
R
+ Input comparator K2
Sync. input
Input undervoltage, ON/OFF
Input overvoltage
Input dynamic current limitation (–)
Input dynamic current limitation (+)
Reference voltage
Supply voltage
Output Q2
Output Q1
Sync. output
Soft start
VCO
R
T
Capacitance
VCO
C
T
R
R
C
R
I COMP
I SYNC
IUV
IOV
–
I
DYN
+
I
DYN
+
V
REF
+
V
S
Q2
Q1
Q SYNC
C
soft start
R
T
C
filter
C
T
Circuit Description
Voltage Controlled Oscillator (VCO)
The VCO generates a sawtooth voltage. The duration of the falling edge is determined
by the value of
C
T
. The duration of the rising edge of the waveform and, therefore,
approximately the frequency, is determined by the value of
R
T
. By varying the voltage at
C
filter
, the oscillator frequency can be changed by its rated value. During the fall time, the
VCO provides a trigger signal for the ramp generator, as well as an L signal for a number
of IC parts to be controlled.
Semiconductor Group
5
INFINEON [ INFINEON TECHNOLOGIES AG ]
