L6590 View Datasheet(PDF) - STMicroelectronics

Part Name

Description

Manufacturer

L6590

FULLY INTEGRATED POWER SUPPLY

STMicroelectronics 

L6590

At turn-on, there are large current spikes due to the discharge of parasitic capacitances and, in case of Contin-

uos Conduction Mode operation, to secondary diode reverse recovery as well, which could falsely trigger the

OCP comparator. To increase noise immunity the output of the OCP comparator is blanked for a short time

(about 120 ns) just after the MOSFET is turned on, so that any disturbance within this time slot is rejected (Lead-

ing Edge Blanking).

Figure 37. OCP internal schematic

DRAIN

Max. Duty cycle

S

OSCILLATOR Clock

R

+

PWM

-

Clock

Driver

Q

1

+

OCP

1/100

Rsense

-

LEB

0.5 V

GND

Thermal Shutdown

Overheating of the device due to an excessive power throughput or insufficient heatsinking is avoided by the

Thermal Shutdown function. A thermal sensor monitors the junction temperature close to the power MOSFET

and, when the temperature exceeds 150 °C (min.), sets an alarm signal that stops the operation of the device.

This is a not-latched function and the power MOSFET is re-enabled as the temperature falls about 40 °C.

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