ZHCSR87 December 2022 DRV8316C
PRODUCTION DATA
The power loss in DRV8316C include standby power losses, LDO and Buck power losses, FET conduction and switching losses, and diode losses. The FET conduction loss dominates the total power dissipation in DRV8316C. At start-up and fault conditions, the output current is much higher than normal current; remember to take these peak currents and their duration into consideration. The total device dissipation is the power dissipated in each of the three half bridges added together. The maximum amount of power that the device can dissipate depends on ambient temperature and heatsinking. Note that RDS,ON increases with temperature, so as the device heats, the power dissipation increases. Take this into consideration when designing the PCB and heatsinking.
A summary of equations for calculating each loss is shown below for trapezoidal controland field-oriented control.
|
Loss type |
Trapezoidal |
Field-oriented control |
|---|---|---|
|
Standby power |
Pstandby = VM x IVM_TA | |
|
LDO |
PLDO = (VM-VAVDD) x
IAVDDD, if BUCK_PS_DIS = 1b PLDO = (VBK-VAVDD) x IAVDDD, if BUCK_PS_DIS = 0b |
|
|
FET conduction |
PCON = 2 x (IPK(trap))2 x Rds,on(TA) | PCON = 3 x ( IRMS(FOC))2 x Rds,on(TA) |
|
FET switching |
PSW = IPK(trap) x VPK(trap) x trise/fall x fPWM | PSW = 3 x IRMS(FOC) x VPK(FOC) x trise/fall x fPWM |
|
Diode |
Pdiode = 2 x IPK(trap) x VF(diode)x tDEADTIME x fPWM | Pdiode = 6 x IRMS(FOC) x VF(diode) x tDEADTIME x fPWM |
|
Buck |
PBK = 0.11 x VBK x IBK assuming (ηBK = 90%) |
|