WPMDH1100601 / 171010601
MagI3C Power Module
VDRM – Variable Step Down Regulator Module
Overtemperature protection (OTP)
The junction temperature of the MagI³C power module should not be allowed to exceed its maximum rating. Thermal
protection is implemented by an internal thermal shutdown circuit which activates at 165°C (typ.) causing the device to enter
a low power standby state. In this state, the high-side MOSFET remains off causing VOUT to fall, and additionally the CSS
capacitor is discharged to ground. Thermal protection helps to prevent catastrophic failures in case of accidental device
overheating. When the junction temperature falls back below 150°C (typical hysteresis = 15°C) the SS pin is released, VOUT
rises smoothly, and normal operation resumes.
Zero coil current detection (ZCCT)
The current of the low-side MOSFET is monitored by a zero coil current detection circuit that inhibits the low-side MOSFET
when its current reaches zero until the next on-time. This circuit prevents a negative inductor current and enables the DCM
operating mode. In this way the efficiency at light loads is improved, also because the output capacitor is not discharged by
the negative current.
Start up into pre-biased load
The MagI³C power module will properly start up into a pre-biased output. This start up situation is common in multiple rail
logic applications where current paths may exist between different power rails during the start up sequence. The UVLO
threshold must be set higher than the pre-bias level of the output voltage (see figure below). This will prevent the pre-biased
output from enabling the regulator through the high-side MOSFET body diode.
V
VIN
adjustable
VUVLO
VOUT
t
we-online.com
Würth Elektronik eiSos GmbH & Co. KG – Data Sheet Rev. 1.0
© September 2017
37/54
WURTH [ WURTH ELEKTRONIK GMBH & CO. KG, GERMANY. ]
