ZHCSLM3B August 2020 – May 2024 LP8864-Q1
PRODUCTION DATA
Figure 7-2 shows the critical part of circuitry: boost components, the LP8864-Q1 internal charge pump for gate-driver powering, and powering/grounding of LP8864-Q1 . Schematic example is shown in Figure 7-2.
REFERENCE DESIGNATOR | DESCRIPTION | NOTE |
---|---|---|
RISENSE | 20 mΩ, 3 W | Input current sensing resistor |
RSD | 20 kΩ, 0.1 W | Power-line FET gate pullup resistor |
RSENSE | 30mΩ, 3W | Boost current sensing resistor |
RG | 15Ω, 0.1W | Gate resistor to control the rising/falling time of nMOSFET for EMC |
RUVLO1 | 76.8kΩ, 0.1W | These UVLO resistor settings set the VIN_UVLO rising voltage at 3.75V, VIN_UVLO falling voltage at 3.35V |
RUVLO2 | 20.5kΩ, 0.1W | |
RFB3 | 0Ω, 0.1W | Not needed unless 100kΩ restrictions on resistors |
RFB2 | 100kΩ, 0.1W | Bottom feedback divider resistor |
RFB1 | 910kΩ, 0.1W | Top feedback divider resistor |
RBST_FSET | 3.92kΩ, 0.1W | Boost frequency set resistor (400kHz) |
RISET | 20.8kΩ, 0.1W | Current set resistor (150mA per channel) |
RPWM_FSET | 17.8kΩ, 0.1W | Output PWM frequency set resistor (4.88kHz PWM frequency to avoid audible noise) |
RMODE | 3.92kΩ, 0.1W | Mode resistor (Phase-Shift PWM mode with 0x3B I2C address) |
RLED_SET | 3.92kΩ, 0.1W | LED_SET resistor (4channels configuration) |
CPUMP | 10µF, 10V ceramic | Charge-pump output capacitor |
C2X | 2.2µF, 10V ceramic | Flying capacitor |
CVDD | 4.7µF + 0.1µF, 10V ceramic | VDD bypass capacitor |
CIN | 1 × 33µF, 50V electrolytic + 1 × 10µF, 50V ceramic | Boost input capacitor |
COUT | 1 × 33µF, 50V electrolytic + 1 × 10µF, 50V ceramic | Boost output capacitor |
L1 | 22μH saturation current 6.5A | Boost inductor |
D1 | 50V, 6.5A Schottky diode | Boost Schottky diode |
Q1 | 60V, 15A nMOSFET | Boost nMOSFET |
Q2 | 60V, 15A pMOSFET | Power-line FET |