MB39C011APFT-G-BND-ERE1 Datasheet, PDF (17/53 Pages) Cypress Semiconductor – 2 ch DC/DC Converter IC with Synchronous Rectification

MB39C011A
Notes :
■ The output is stopped by the short-circuit protection (SCP) function when the DC/DC output is short-circuited to GND etc.
However, care needs to be taken because the short-circuit protection (SCP) function will not stop the output when a half
short-circuit occurs. Measures such as placing a fuse in the input can be used for this situation. [ Half short-circuit refers to a
short-circuit condition where an overcurrent flows, but it is not sufficient to reduce the output voltage.]
■ In the event that an output short current flows that exceeds the capacity of the input power supply, the power supply voltage
may drop. If the power supply voltage at this time drops below 3.8 V, the output is stopped by the under voltage lockout
protection circuit (UVLO). However, once the input power supply voltage recovers after the output has been stopped, the
output will begin again. Care needs to be taken because this situation may result in a repeating cycle of “short-circuit →
power-supply voltage drop → output stop → power-supply voltage recovery → output start → short-circuit”. There are putting
a fuse in the input etc. as measures.
■ Notes the short-circuit protection (SCP) function when the DC/DC converter is started/stopped. The output may also be stopped
by the short-circuit protection (SCP) function under the following conditions.
❐ Operations that act on the input power supply and the CTL pin (for example, shorting the input power supply to the CTL pin).
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process.
(1) DC/DC converter output begins when V_IN (  VB) > UVLO threshold voltage.
(2) A period of time occurs where the input power supply voltage (V_IN) < the output voltage setting (V_O), and the duty cycle
becomes 100% on. The error amplifier output rises above 1.9 V due to the feedback control.
(3) The output is stopped after the short-circuit detection time has elapsed.
Document Number: 002-08369 Rev. *A
Page 17 of 53