Hello, I am currently sizing the MP5048 and I have a few questions. I am using it to create a current limiter because my goal is to maintain a fixed voltage while varying the current from 0 to 15A, so the current limit is 15A. However, here are my questions:
My supply voltage (Vin) ranges from 10 to 35V. Is this suitable for the MP5048? I ask this question because the datasheet states “ABSOLUTE MAXIMUM RATINGS: VIN(DC) = -0.3V to +65V” and later “Recommended Operating Conditions: Input voltage operating range = 24V to 60V,” which confuses me. Please let me know if I can supply it with 10 to 35V.
If I apply a voltage of 10V, for example, at the input, can I expect to have the same output voltage of 10V? I ask this because the datasheet states: “ABSOLUTE MAXIMUM RATINGS: VIN(DC) = -0.3V to +65V and VOUT = -0.3V to +65V.”
The datasheet mentions “Current-sense output. CS requires an external resistor. The CS voltage (VCS) is compared to CLREF to determine the current limit.” However, what is the value of VCLREF_NORM? The datasheet states “VOUT ≥ 90% of VIN.” In this case, if VOUT = VIN, is VCLREF_NORM 2V?
How should I size RCLREF? Since the current limit value depends on VCS and VCLREF, is it a fixed value of 53.6kΩ?
Can you provide the equations for ICLREF and RCLREF?2025-09-02T09:20:00Z
Thank you for reaching out to the MPS Technical Forum, I will be happy to answer your questions.
The MP5048 has an Operating Input Range of 24V to 60V. As mentioned in the device’s datasheet page 5 (Note 3): The MP5048 is not guaranteed to function outside of its operating conditions.
That being said, this device will not work for your supply voltage range.
If you need a similar device that is suitable for your supply voltage I would suggest checking out the MPQ5069, its recommended operation is 6V to 28V, and absolute maximum rating of -0.3V to +36V.
Following up from the previous question, applying 10V to the input pin does not assures an output voltage of 10V as this value is outside of the device’s operating input range.
VCLREF_NOM is stated to be the CLREF pin voltage during “Normal Operation,” which is the voltage after soft start.
For instance, you could use a controller like the MP5920 that can regulate the current limit by regulating the voltage fed to the CLREF pin on the MP5048. If not using a controller, then the MP5048 can generate a voltage on the CLREF pin using the Internal Current Source (ICLREF) of 26uA stated on page 6 of the datasheet and a shunt resistor (RCLREF).
For sizing the RCLREF resistor you need to choose a voltage value for the CLREF pin. For instance, let’s assume you want a VCLREF value of 1.5V, then you can find RCLREF using the following equation: RCLREF = VCLREF / ICLREF.
So RCLREF is equal to 1.5V / 26uA ~ 57.7kOhm.
On page 6 of the device’s datasheet it is stated that ICLREF is 26uA. For RCLREF you can use the equation: RCLREF = VCLREF / ICLREF.