SLUSEQ9D July 2022 – April 2024 TPS1211-Q1
PRODUCTION DATA
TPS1211x-Q1 features an accurate analog load current monitor output (IMON) with adjustable gain. The current source at IMON terminal is configured to be proportional to the current flowing through the RSNS current sense resistor. This current can be converted to a voltage using a resistor RIMON from IMON terminal to GND terminal. This voltage, computed using Equation 11 can be used as a means of monitoring current flow through the system.
Use Equation 11 to calculate the V(IMON).
Where VSNS = I_LOAD × RSNS and V(OS_SET) is the input referred offset (± 200 µV) of the current sense amplifier (VSNS to V(IMON) scaling). Use the following equation to calculate gain.
The maximum voltage range for monitoring the current (V(IMONmax)) is limited to minimum([V(VS) – 0.5V], 5.5V) to ensure linear output. This puts limitation on maximum value of RIMON resistor. The IMON pin has an internal clamp of 6.5 V (typical).
Accuracy of the current mirror factor is < ± 1%. Use the following equation to calculate the overall accuracy of V(IMON).
Figure 8-14 shows external connections and simplified block diagram of current sensing and overcurrent protection implementation.
In TPS12110-Q1 and TPS12111-Q1, IMON amplifer output is turned OFF when PD is pulled low to SRC (due to INP pulled low or fault event) whereas IMON output remains enabled in TPS12112-Q1 even if PD is pulled low to SRC. In TPS12112-Q1, IMON output gets disabled only when the device is disabled by pulling EN/UVLO low below V(ENF) or V(VS) below V(VS_PORF).
TPS12112-Q1 can be used in applications where grouped IMON output is desired as shown in Figure 8-13: