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ZHCSPJ0C april 2022 – august 2023 TPSI3050

PRODUCTION DATA

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机械数据 (封装 | 引脚)

DWZ|8
- MPSS140

散热焊盘机械数据 (封装 | 引脚)

订购信息

9.2.2.6 Gate Driver Output Resistor

The optional external gate driver resistors, R_GSRC and R_GSNK, along with the diode are used to:

Limit ringing caused by parasitic inductances and capacitances
Limit ringing caused by high voltage switching dv/dt, high current switching di/dt, and body-diode reverse recovery
Fine-tune gate drive strength for sourcing and sinking
Reduce electromagnetic interference (EMI)

The TPSI3050 has a pullup structure with a P-channel MOSFET with a peak source current of 1.5 A. Therefore, the peak source current can be predicted with:

Equation 7.

I_{O +} ≅ m i n (1.5 A, \frac{V_{V D D H}}{R_{D S O N_V D R V} + R_{G S R C} + R_{G F E T_I N T}})

where

R_GSRC: external turn-on resistance.
R_{DSON_VDRV}: TPSI3050 driver on resistance in high state. See Electrical Characteristics.
V_VDDH: VDDH voltage. Assumed 10.2 V in this example.
R_{GFET_INT}: external power transistor internal gate resistance, found in the power transistor data sheet. Assume 0 Ω for this example.
I_O+: peak source current. The minimum value between 1.5 A, the gate driver peak source current, and the calculated value based on the gate drive loop resistance.

For this example, R_{DSON_VDRV} = 2.5Ω, R_GSRC = 8 Ω, and R_{GFET_INT} = 0 Ω results in:

Equation 8.

I_{O +} ≅ m i n (1.5 A, \frac{10.2 V}{2.5 Ω + 8 Ω + 0 Ω}) = 0.97 A

Similarly, the TPSI3050 has a pulldown structure with an N-channel MOSFET with a peak sink current of 3.0 A. Therefore, assuming R_{GFET_INT} = 0 Ω, the peak sink current can be predicted with:

Equation 9.

I_{O -} ≅ m i n [3.0 A, (V_{V D D H} \times (R_{G S R C} + R_{G S N K}) - R_{G S R C} \times V_{F}) \times \frac{1}{{R_{G S R C} \times R_{G S N K} + R}_{D S O N_V D R V} \times (R_{G S R C} + R_{G S N K})}]

where

R_GSRC: external turn-on resistance.
R_GSNK: external turn-off resistance.
R_{DSON_VDRV}: TPSI3050 driver on resistance in low state. See Electrical Characteristics.
V_VDDH: VDDH voltage. Assumed 10.2 V in this example.
V_F: diode forward voltage drop. Assumed 0.7 V in this example.
I_O-: peak sink current. The minimum value between 3.0 A, the gate driver peak sink current, and the calculated value based on the gate drive loop resistance.

For this example, assuming R_{DSON_VDRV} = 1.7 Ω, R_GSRC = 8 Ω, R_GSNK = 4.5 Ω, and R_{GFET_INT} = 0 Ω, results in:

Equation 10.

I_{O -} ≅ m i n [3.0 A, (10.2 V \times (8 Ω + 4.5 Ω) - 3.5 Ω \times 0.7 V) \times \frac{1}{8 Ω \times 4.5 Ω + 1.7 Ω \times (8 Ω + 4.5 Ω)}] = 2.18 A

Importantly, the estimated peak current is also influenced by PCB layout and load capacitance. Parasitic inductance in the gate driver loop can slow down the peak gate drive current and introduce overshoot and undershoot. Therefore, TI strongly recommends to minimize the gate driver loop.