TDA 4700
TDA 4718
Pin Definitions and Functions (TDA 4718)
Pin
Symbol
Function
1
GND
Ground 0 V
2
3
RR
CR
Ramp generator RR
Ramp generator CR
4
5
I COMP
I SYNC
+ Input comparator K2
Sync. input
6
7
IUV
IOV
Input undervoltage, ON/OFF
Input overvoltage
8
9
– IDYN
+ IDYN
Input dynamic current limitation (–)
Input dynamic current limitation (+)
10
11
+ VREF
+ VS
Reference voltage
Supply voltage
12
13
Q 2
Q 1
Output Q2
Output Q1
14
15
Q SYNC
Csoft start
Sync. output
Soft start
16
17
18
RT
Cfilter
CT
VCO RT
Capacitance
VCO CT
Circuit Description
Voltage Controlled Oscillator (VCO)
The VCO generates a sawtooth voltage. The duration of the falling edge is determined
by the value of CT. The duration of the rising edge of the waveform and, therefore,
approximately the frequency, is determined by the value of RT. By varying the voltage at
Cfilter, 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 ]
