TLE4305_08 Datasheet, PDF (13/16 Pages) Infineon Technologies AG – Voltage-Current Regulator Wide supply voltage operation range

TLE 4305
Current Loop TLE 4305
V_Q
C_CRE
100 nF
from Voltage Loop
V_REF
R_I1
25 kΩ
Control
Logic
Driver
1 kΩ _OUT
D2
CSE ^RI1
C-OTA
CRE ^{25 kΩ}
R_{CC CCO}
1 kΩ
R_Sense
R_CRE
10 kΩ
C_CCO
10 nF
AES02881
Figure 8 Improved Current Control Loop
The calculation of the current is identical to the above calculation (Equation (6)). The
voltage at resistor R_CRE can be neglected (typical 2 mV for 10 kΩ resistor). The resistor
R_CRE and the Capacitor C_CRE improve further the current control loop response.
Supply of the TLE 4305
The TLE 4305 is an active circuitry and requires a supply voltage at pin V_S. During start
up of the supply, there is no energy stored in the load capacitor. Dependent on the
required output voltage also during operation the output voltage might be too small.
Therefore a second transformer-winding n3 is required. The voltage charges the input
capacitor C_S though the diode D1. Internally the TLE 4305 generates for input voltages
above 8 V a preregulated 6 V internal rail. The device generates biasing currents and
reference voltages from this rail.
To avoid Ground and V_Q-shifts, all GND connections should be connected to one point
as well as all V_Q-signals.
If the application requires more than one voltage linear post-regulators can be used. In
the application a choke should be placed in series. An electrolyte or tantalum capacitor
of 10 µF to 100 µF should be used in parallel to a 10 to 100 nF ceramic capacitor to filter
high frequency noise. The size of the choke and the capacitors depend on the
application requirements.
Data Sheet
13
Rev. 2.2, 2008-11-17