LTC3731H_15 Datasheet, PDF (24/34 Pages) Linear Technology – 3-Phase, 600kHz, Synchronous Buck Switching Regulator Controller

LTC3731H
Applications Information
SW1
D1
L1
R_SENSE1
V_IN
R_{IN +}
C_IN
SW2
D2
L2
R_SENSE2
V_OUT
+
C_OUT
R_L
BOLD LINES INDICATE HIGH,
SWITCHING CURRENTS.
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 F12
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 pos-
sible to the IC.
Figure 11 illustrates all branch currents in a three-phase
switching regulator. It becomes very clear after study-
ing the current waveforms why it is critical to keep the
high switching current paths to a small physical size.
High electric and magnetic fields will radiate from these
“loops” just as radio stations transmit signals. The output
capacitor ground should return to the negative terminal
3731Hfb