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26 lines
1.2 KiB
Plaintext
26 lines
1.2 KiB
Plaintext
C3 Main Circuit breaker design notes
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Part TI - TPS259621
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This information is all from the data sheet.
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1. Pins 2 and 8 are left intentionaly open. Pin 2 is to set a longer inrush
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slew rate and pin 8 is left open to set 13.7V as the over voltage clamp set
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point [p21].
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2. The Voltage divider on pin 3 sets the under voltage set point as follows
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VIN_(UV) = V_UVLO*(R1+R2)/R2. [p19] Where V_UVLO = 1.2 V [p7], VIN_(UV) is the threshold
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at which the IC turns on the power rail and R1(top resistor) = 10k R2(bottom resistor) = 31.7k.
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With this config undervoltage lockout is 5V.
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3. The resistor at pin 7 sets the limit current according to the equation
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R_ILM (Ohms) = 903 / (I_LIM (A) - 0.0112) [p22]. With the R_ILM = 3.1k, I_LIM = 0.302 (A).
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You can also monitor the input current by routing this pin to an analog input
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on the MCU.
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4. Pin 6 is left open because this is pulled low when the IC cuts power to
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the rail. If that happens the MCU wont be there to see this pin go low anyay.
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5. This part is an auto retry. If an overvoltage or over current condition
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persists, it enters thermal shutdown at 157 C and cuts power to the rail [p7]. It then
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restablishes power after it has cooled down 11.5 C and 95 ms have elapsed [p8].
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