JAJSON6A July 2023 – December 2023 INA740A , INA740B
PRODMIX
The INA740x has a full scale ADC range for current measurements of ±39.32 A. However, the maximum value that can be measured is limited by the operating junction temperature (see Figure 7-15).
Table 7-4 shows the full scale value for shunt, bus, and temperature measurements, along with their associated step size.
PARAMETER | REGISTER ADDRESS | SIZE | FULL SCALE VALUE | RESOLUTION |
---|---|---|---|---|
Current | 7h | 16 bit, signed | ±39.32 A | 1.2 mA/LSB |
Bus voltage | 5h | 16 bit, signed, always positive | 0 V to 85 V | 3.125 mV/LSB |
Die Temperature | 6h | 12 bit, signed | –40°C to +150°C | 125 m°C/LSB |
Power | 8h | 24 bit, unsigned | 4026.53W | 240 µW/LSB |
Energy | 9h | 40 bit, unsigned | 4222.125 MJ | 3.840 mJ/LSB |
Charge | Ah | 40 bit, unsigned | 82.463 MC | 75 µC/LSB |
The internal die temperature sensor register range extends from –256°C to +256°C but is limited by the junction temperature range of –40°C to 150°C. Likewise, the bus voltage measurement range extends up to 102.4 V but is limited by silicon to 85 V.
Current, bus voltage, temperature, power, energy and charge measurements can be read through their corresponding address registers. Values are calculated by multiplying the returned value by the corresponding LSB size.
Signed values are represented in 2's complement format.
Upon overflow, the ENERGY register will roll over and start from zero. This register value can also be reset at any time by setting the RSTACC bit in the CONFIG register.
An overflow event in the CHARGE register is indicated by the CHARGEOF bit. If an overflow condition occurs, the CHARGE register needs to be manually reset by setting the RSTACC bit in the CONFIG register.
For a design example using these equations refer to Detailed Design Procedure.