TLE4305 Datasheet, PDF (11/15 Pages) Infineon Technologies AG – Voltage-Current Regulator

TLE 4305
Voltage Control Loop
Voltage Loop TLE 4305
from Current Loop
V_Q
R_V1
VSE
V-OTA
R_V2
V_REF
Control
Logic
Driver
1 kΩ
OUT
R_VC
1 kΩ
VCO
C_VCO
10 nF
AES02883
Figure 6 Voltage Loop
The voltage loop regulator compares the input voltage V_SE to a reference voltage V_ref of
typical 2.5 V. The difference is attenuated and proportional current drives the opto
isolator. The control loop output voltage V_Q, pin VSE, pin OUT, opto isolator, primary
regulator and the transformer close the loop.
To program an output voltage a divider is used. The resistors are chosen according to
Equation (5).
V_VSE = V_ref
(3)
V_VSE = V_Q × R_V2 / (R_V1 + R_V2)
(4)
with V_ref typical 2.5 V
V_Q = V_VSE × (R_V1 + R_V2) / R_V2
(5)
To compensate the voltage loop a 10 nF capacitor should be connected to pin VCO. With
the internal 1 kΩ resistor it reduces the overall closed voltage loop’s bandwidth.
If the gain of the overall loop has to be adapted to the application’s needs, the output
capacitor can be modified accordingly.
Data Sheet
11
Rev. 2.1, 2004-01-01