SLVSG23C December 2021 – August 2022 DRV8243-Q1
PRODUCTION DATA
The device offers an optional internal load current regulation feature using fixed TOFF time method. This is done by comparing the voltage on the IPROPI pin against a reference voltage determined by ITRIP setting. TOFF time is fixed at 30 µsec for HW variant, while it is configurable between or 20 to 50 µsec for the SPI variant using TOFF_SEL bits in the CONFIG3 register.
The ITRIP regulation, when enabled, comes into action only when the HS FET is enabled and current sensing is possible. In this scenario, when the voltage on the IPROPI pin exceeds the reference voltage set by the ITRIP setting, the internal current regulation loop forces the following action:
Current limit is set by the following equation:
In Independent mode, since ITRIP regulation is based on summation of the two half-bridge currents on IPROPI pin, it is not possible to have completely independent current regulation for the two half-bridges simultaneously.
The ITRIP comparator output (ITRIP_CMP) is ignored during output slewing to avoid false triggering of the comparator output due to current spikes from the load capacitance. Additionally, in the event of transition from low-side recirculation, an additional blanking time tBLANK is needed for the sense loop to stabilize before the ITRIP comparator output is valid.
ITRIP is a 6-level setting for the HW variant. The SPI variant offers two more settings. This is summarized in the table below:
ITRIP Pin | S_ITRIP Register Bits | VITRIP [V] |
---|---|---|
RLVL1OF6 | 3'b000 | Regulation Disabled |
RLVL2OF6 | 3'b001 | 1.18 |
Not available | 3'b010 | 1.41 |
Not available | 3'b011 | 1.65 |
RLVL3OF6 | 3'b100 | 1.98 |
RLVL4OF6 | 3'b101 | 2.31 |
RLVL5OF6 | 3'b110 | 2.64 |
RLVL6OF6 | 3'b111 | 2.97 |
In the HW variant of the device, the ITRIP pin changes are transparent and changes are reflected immediately.
In the SPI variant of the device, the ITRIP setting can be changed at any time when SPI communication is available by writing to the S_ITRIP bits. This change is immediately reflected in the device behavior.
SPI variant only - If the ITRIP regulation levels are reached, the ITRIP_CMP bit in the STATUS1 register is set. There is no nFAULT pin indication. This bit can be cleared with a CLR_FLT command.