STEVAL-ISA039V1 STMicroelectronics, STEVAL-ISA039V1 Datasheet - Page 14

• Manufacturer Part Number: STEVAL-ISA039V1
• Description: BOARD EVAL BASED ON L6727
• Manufacturer: STMicroelectronics
• Type: DC/DC Switching Converters, Regulators & Controllersr

Specifications of STEVAL-ISA039V1

• Design Resources: STEVAL-ISA039V1 Gerber Files L6727 Eval Board Schematic STEVAL-ISA039V1 Bill of Materials
• Main Purpose: DC/DC, Step Down
• Outputs And Type: 1, Non-Isolated
• Voltage - Output: 1.25V
• Current - Output: 5A
• Voltage - Input: 5 ~ 12V
• Regulator Topology: Buck
• Frequency - Switching: 300kHz
• Board Type: Fully Populated
• Utilized Ic / Part: L6727
• Input Voltage: 5 V to 12 V
• Output Voltage: 1.25 V
• Product: Power Management Modules
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Power - Output: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• For Use With/related Products: L6727
• Other names: 497-8266

Output voltage monitor and protections
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8.1
8.2
8.3
8.4
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Output voltage monitor and protections
L6727 monitors the voltage at FB pin and compares it to internal reference voltage in order
to provide Under Voltage and Over Voltage protections.
Undervoltage protection
If the voltage at FB pin drops below UV threshold (0.6 V typ), the device turns off both HS
and LS MOSFETs, waits for 2048 clock cycles and then performs a new soft start. If under
voltage condition is not removed, the device enters a hiccup mode with a typical period of
13.6 ms.
UVP is active from the end of soft start.
Overvoltage protection
If the voltage at FB pin rises over OV threshold (1 V typ), over voltage protection turns off HS
MOSFET and turns on LS MOSFET overriding PWM logic as long as over voltage is
detected.
OVP is always active with top priority as soon as over current threshold setting phase has
been completed.
Feedback disconnection protection
In order to provide load protection even if FB pin is not connected, a 100 nA bias current is
always sourced from this pin. If FB pin is not connected, this current will permanently pull up
FB over OVP threshold: thus LS will be latched on preventing output voltage from rising out
of control.
Undervoltage lock out
In order to avoid anomalous behaviors of the device when the supply voltage is too low to
support its internal rails, UVLO is provided: the device will start up when VCC reaches
UVLO upper threshold and will shutdown when VCC drops below UVLO lower threshold.
The 4.1 V maximum UVLO upper threshold allows L6727 to be supplied from 5 V and 12 V
busses in or-ing diode configuration.
Doc ID 12933 Rev 4
L6727