LTC3731H Datasheet, PDF (24/32 Pages) Linear Technology – 3-Phase, 600kHz, Synchronous Buck Switching Regulator Controller

LTC3731H
APPLICATIO S I FOR ATIO
SW1
D1
L1
R_SENSE1
V_IN
R_IN
+
C_IN
L2
V_OUT
SW2
R_SENSE2
+
D2
C_OUT
R_L
BOLD LINES INDICATE HIGH,
SWITCHING CURRENT LINES.
KEEP LINES TO A MINIMUM
LENGTH
SW3
D3
L3
R_SENSE3
24
3731H F11
Figure 11. Branch Current Waveforms
INDUCTOR
LTC3731H
SENSE⁺
SENSE^–
1000pF
SENSE
RESISTOR
3731H F12b
OUTPUT CAPACITOR
Figure 12. Kelvin Sensing R_SENSE
7) The 47pF to 330pF ceramic capacitor between the I_TH
pin and signal ground should be placed as close as
possible to the IC.
Figure 11 illustrates all branch currents in a three-phase
switching regulator. It becomes very clear after studying
the current waveforms why it is critical to keep the high
switching current paths to a small physical size. High elec-
tric and magnetic fields will radiate from these “loops” just
as radio stations transmit signals. The output capacitor
3731hf