SNVSBJ0B December 2019 – August 2021 LM5170
PRODUCTION DATA
The LM5170 monitors the real time inductor current in each channel at the IOUT1 and IOUT2 pins. The channel current is converted to a small current source scaled by the factors seen in Equation 11 and Equation 12:
where
The DC offset current is introduced to raise the no-load signal above the possible ground noise floor. Since the monitor signal is in the form of current, an accurate reading can be obtained across a termination resistor even if the resistor is located far from the LM5170 but close to the MCU, thus rejecting potential ground differences between the LM5170 and the MCU. Figure 8-6 shows a typical channel current monitor through a 9.09-KΩ termination resistor and a 10-nF to 100-nF ceramic capacitor in parallel. The RC network converts the current monitor signal into a DC voltage proportional to the channel DC current. For example, when the current sense voltage DC component is 50 mVdc, namely VCS_dc = 50 mV, the termination RC network produces a DC voltage of 2.5 V. Note that the maximum IOUT pin voltage is internally clamped to approximately 4 V.