Table of Contents
Advertisement
2ED4820-EM EB2 2HSV48
Table of contents
Figure 14
End of charge detector.
The voltage out of the resistive path, which is charging the capacitor, is compared to a reference voltage
generated from the supply voltage supplying the board.
R38 & R39 divide the voltage on the capacitor: CP+ is biased to 12/(270+12) = 4.255 % of OUT1 voltage.
•
R40, R41 & R42 divide the voltage of the supply: R41 // R42 is : (10*270)/(10+270) = 9.64 kΩ, so CP- is biased to
•
(9.64) / (270+9.64 ) = 3.448 % of the supply voltage applied on VBAT_GD.
The comparator output is triggered when CP+ = CP-, which means:
[ 4.25 % x V(OUT1) ] = [ 3.448 % x V(VBAT_GD) ] → V(OUT1) = 0.03448/0.04255 x V(VBAT_GD)
→ V(OUT1) = 81% V(VBAT_GD).
The comparator output is triggered when the voltage on the capacitor has reached 81 % of the supply rail.
The value of R42 can be modified to change this percentage if required:
Table 1
Percentage of VBAT_GD for which the comparator triggers
Value of R42 (kΩ)
Percentage of VBAT_GD
User Manual
www.infineon.com
none
270
120
87 %
81 %
77.7 %
page 11 of 26
56
39
27
71.6 %
67.3 %
61.8 %
1.0
2022-01-20
Advertisement
Table of Contents
