L6599A STMicroelectronics, L6599A Datasheet - Page 5

• Manufacturer Part Number: L6599A
• Description: IMPROVED HIGH-VOLTAGE RESONANT CONTROLLER
• Manufacturer: STMicroelectronics

Specifications of L6599A

• Two-level Ocp: frequency-shift and latched shutdown

L6599A
3
Pin connection
Figure 2.
Table 2.
Pin N#
1
2
3
Pin connection (top view)
Pin description
DELAY
Type
Css
CF
Soft-start. This pin connects an external capacitor to GND and a resistor to
RFmin (pin 4) that set both the maximum oscillator frequency and the time
constant for the frequency shift that occurs as the chip starts up
(soft-start). An internal switch discharges this capacitor every time the chip
turns off (Vcc < UVLO, LINE < 1.24 V or > 6 V, DIS > 1.85 V, ISEN > 1.5 V,
DELAY > 2 V) to make sure it will be soft-started next, and when the
voltage on the current sense pin (ISEN) exceeds 0.8 V, as long as it stays
above 0.75 V.
Delayed shutdown upon overcurrent. A capacitor and a resistor are
connected from this pin to GND to set the maximum duration of an
overcurrent condition before the IC stops switching and the delay after
which the IC restarts switching. Every time the voltage on the ISEN pin
exceeds 0.8 V the capacitor is charged by an internal 150 µA current
generator and is slowly discharged by the external resistor. If the voltage
on the pin reaches 2 V, the soft start capacitor is completely discharged so
that the switching frequency is pushed to its maximum value and the
150 µA is kept always on. As the voltage on the pin exceeds 3.5 V the IC
stops switching and the internal generator is turned off, so that the voltage
on the pin will decay because of the external resistor. The IC will be soft-
restarted as the voltage drops below 0.3 V. In this way, under short circuit
conditions, the converter will work intermittently with very low input
average power.
Timing capacitor. A capacitor connected from this pin to GND is charged
and discharged by internal current generators programmed by the external
network connected to pin 4 (RFmin) and determines the switching
frequency of the converter.
Doc ID 15308 Rev 5
Function
Pin connection
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