There is a question about the soft start of TPS65150.
（Please look at the 13th page of the data sheet. ）
１．Is the clock cycles equal to switching frequency?
２．Does the start-up time of input voltage have restriction? ・Is it required 5ms or more?
・Do any problems occur at the time of less than 5ms?
３．Is the input voltage power supply of the characteristic data of data sheet figure 8 supplied?
I would appreciate your favor which will be saved if you can advise .
Hello Satoshi,
Here the answers to your questions:
[Brigitte] The clock cycle is given by the oscillator frequency in the elecrical characteristics table.
[Brigitte] The softstart starts when the input voltage is higher than UVLO. As long as the source is able to deliver the current, I do not see a problem.
[Brigitte] What do you mean with this? You can see the input voltage as the top waveform.
Best regards,
Brigitte
Hello Brigitte ,
Thank you for giving advice instantly. Moreover, I answer about the following inquiry.
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[Answer]
I want to know the input voltage of power supply circuit in Fig.8.
(For example, Is it the composition which is using the DC ragulated power supply? )
Satoshi
Still I am not sure, if I understand you correctly. When you have a look on Figure 23, there is a schematic for 5V supply, VIN connection in this schematic is the same as used for Figure 8.
So the 5V is connected to a lab power supply and this lab power supply starts with the rate you can see in Figure 8.
Best regards,Brigitte
Hello Brigitte,
Thank you for the advice. Moreover, I received the question in the following addition about current limit.
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When is the first step of current Limit begins to move ? - After the Q1 switching start or The input voltage is higher than UVLO?
I would appreciate your favor.
The IC will start the softstart procedure when the voltage comes out of UVLO and the output voltage of the boost converter almost reached the input voltage. So the softstart starts when the boost converter starts to switch.