MLX83202 Datasheet, PDF (28/35 Pages) Melexis Microelectronic Systems – Automotive NFET pre-drivers

MLX83202/MLX83203
Automotive NFET pre-drivers
8.7.2 FET driver during sleep mode
When the MLX83203 is in sleep mode a gate discharge resistance (Rsgd~1kOhm) is activated which
ensures the FET gates remain fully in OFF state.
Note that is the responsibility of the microcontroller to ensure all gate voltages are low, for instance by setting
the EN input low, prior to switching to sleep mode.
Figure 13. State of pre-driver in sleep mode
Figure 13 PHASEx is kept low with GATETx through the internal body diode of the pre-driver.
8.8 Charge pump
EEPROM configuration bits
CPMODE
EN_CP
1: VBOOST voltage is regulated relative to VSUP.
0: VBOOST voltage is regulated relative to ground
1: enables boost charge pump
0: disables boost charge pump
Table 15. CP configuration in EEPROM
Default
0
1
Standard operation of the Charge pump (CPMODE=0) is to ensure sufficient gate voltage to the bootstrap
capacitors in case of low battery voltage conditions. In this case VBOOST is regulated compared to GND
level. The charge pump will not be switching when VSUP > VREG + 2* Vf, with Vf= forward voltage of the
charge pump diodes.
Alternatively (CPMODE=1) the charge pump can regulate VBOOST compared to VSUP. In this case the
Cboost cap should be connected to VSUP to ensure any supply variations are coupled to the VBOOST level.
In this case VBOOST can be applied to drive a high side reverse polarity NFET.
The disadvantage is an additional amount of dissipation inside the driver to regulate VREG.
3901083203
Rev 2.2
Page 28 of 35
Prelim. Data Sheet
4 Dec 2013