SI8513-C-IS Datasheet, PDF (21/37 Pages) List of Unclassifed Manufacturers – Si85XX UNIDIRECTIONAL AC CURRENT SENSORS

Si85xx
3.4. Single-Phase Buck Converter Example
In this example, the Si850x is configured to operate in a single-phase synchronous buck converter (Figure 18).
This converter has a PWM frequency of 1 MHz and a maximum duty cycle of 80%.
This is an example of a half-wave application that can be addressed with Single-Ended output mode. The PWM
period is calculated to be 1/10^–6 = 1.0 µs, and the worst-case value, t_R, is 0.2 x 1.0 x 10^–6 = 200 ns at 80%
maximum duty cycle (R_TRST = 20 k).
In this example, the current measurement is made when the buck switch is on; so, PH2 is chosen as the reset
signal by connecting PH2 to R1 and grounding R2. The PH2 signal can be obtained at the input of the driver
external to the PWM controller or the output of the controller's internal driver (through a resistor divider if the driver
output swings beyond the device VDD range).
C1
0.1 µF
VDD
C2
1 µF
VIN
VDD1 VDD2 IIN
R2
R_TRST
TRST
R1
Si850x
IOUT
GND1
GND2
GND3
OUT
2 Vpp
PH1
PH2
Q1
PWM
L1
VOUT
PH2
Current I = 0
I>0
C3
Q2
Si850x State
RESET MEASURE
100 ns
Figure 18. Si850x Single-Phase Buck Converter
Preliminary Rev. 0.4
21