ZHCSR16 September 2022 TPS544C26
ADVANCE INFORMATION
The telemetry sub-system in the controller core supports the following measurements:
The ADC output is a single conversion of each measurement without rolling window averaging for fast refresh rate of these key system parameter. All above parameters are measured sequentially while the Input current and Output current are measured more often than the others. This sequence design allows each IIN or IOUT telemetry value to be updated within 95 µs, while each of the rest of telemetry value to be updated within 190 µs.
The input voltage sense telemetry senses the voltage level on pin 4 VINSENM. The device offers internal divider to minimize the external component count and save solution size. The VIN reporting range is limited from 8 V to 16 V to improve the reporting resolution. For any VIN value less than 8 V, the VIN reports 8 V. For any VIN value higher than 16 V, the VIN reports 16 V. For example, the READ_VIN reports 8 V for a VIN = 6 V condition. The VIN conversion equation is:
Where
The input current sense telemetry senses the differntial voltage level across pin 3 VINSENP and pin 4 VINSENM. A high accuracy sensing resistor in series with the input bus is commonly used for this feature. Together with the setting in (B3h) PIN_SENSE_RES register, the ADC converts the sensed differential voltage to input current in amp. The device offers internal gain stage to minimize the external component count and save solution size. Given the sensed differential voltage is in millivolts range and to avoid impact from the switching noise on the input bus, a ceramic bypass capacitor is required on each pin (pin 3 VINSENP and pin 4 VINSENM) referring to PGND and the recommended value is at least 100 pF with X7R temperature characterisitic. The IIN conversion equation is:
Where
The input power reported in (97h) READ_PIN register is a simple calculation, which is the product of the measured raw input voltage and the measured raw input current. The calculation does not use the register value in (88h) READ_VIN and (89h) READ_IIN. The PIN conversion equation is:
Where
When input power feature is not used, follow below connection for pin 3 VINSENP and pin 4 VINSENM so that the device can report the input voltage level on PVIN node:
The output voltage sense telemetry senses the differential voltage across VOSNS to GOSNS pin. The conversion equation for VOUT is related with VOUT step (5 mV or 10 mV) which is defined by PROTOCOL_ID bits in I2C (C2h) PROTOCOL_ID_SVID register.
The VOUT conversion equation for 5 mV step is:
The VOUT conversion equation for 10 mV step is:
Where
The output current sense telemetry senses the average of low-side FET current from the start to the end of each low-side FET on time which provides the average inductor current. To achieve high accuracy and wide report range, the device automatically sets the current sense gain based on ICC_MAX setting in (C0h) ICC_MAX register. When the ICC_MAX is equal or greater than 15 A, the current sense gain is set to a smaller value to achieve wide report range. When the ICC_MAX is equal or less than 10 A, the current sense circuit uses a higher gain to get a significant amplitude and achieve good accuracy. The change of gain setting does not affect the positive overcurrent limit (OCL) threshold but affect the negative overcurrent (NOC) threshold. The IOUT conversion equation is:
Where
The die temperature sense telemetry senses the controller die temperature. The power stage die implementes its own over-temperature protection and power stage die temperature is not reported through temetry sub-system. The IC Temperature conversion equation is:
Where