L6599 STMicroelectronics, L6599 Datasheet - Page 29

• Manufacturer Part Number: L6599
• Description: High-voltage resonant controller
• Manufacturer: STMicroelectronics

Specifications of L6599

• Dimensions (l/w/h): 132 mm / 52 mm / 22 mm
• Universal Ac Mains Range: 90 VAC to 264 VAC
• High Output Power: 90 W (4.74 A, 19 VDC)
• Very Low Output Noise And Ripple: less than 300 m VP-P
• Very Low Standby Power: less than 0.5 W at 264 V
• Hiccup Mode: Auto recovery with SCP
• Latch Mode: OVP acts while VOUT > 29 VDC

L6599
7.7
voltage on the pin exceeds 7 V the device is shutdown. If its supply voltage is always above
the UVLO threshold, the IC will restart as the voltage falls below 7 V.
The LINE pin, while the device is operating, is a high impedance input connected to high
value resistors, thus it is prone to pick up noise, which might alter the OFF threshold or give
origin to undesired switch-off of the IC during ESD tests. It is possible to bypass the pin to
ground with a small film capacitor (e.g. 1-10 nF) to prevent any malfunctioning of this kind. If
the function is not used the pin has to be connected to a voltage greater than 1.25 V but
lower than 6V (worst-case value of the 7 V threshold).
Bootstrap section
The supply of the floating high-side section is obtained by means of a bootstrap circuitry.
This solution normally requires a high voltage fast recovery diode to charge the bootstrap
capacitor C
It is realized by means of a high voltage DMOS, working in the third quadrant and driven
synchronously with the low side driver (LVG), with a diode in series to the source, as shown
in
Figure 34. Bootstrap supply: internal bootstrap synchronous diode
The diode prevents any current can flow from the VBOOT pin back to V
supply is quickly turned off when the internal capacitor of the pump is not fully discharged.
To drive the synchronous DMOS it is necessary a voltage higher than the supply voltage
V
The bootstrap structure introduces a voltage drop while recharging C
side driver is on), which increases with the operating frequency and with the size of the
external power MOSFET. It is the sum of the drop across the R
across the series diode. At low frequency this drop is very small and can be neglected but,
as the operating frequency increases, it must be taken into account. In fact, the drop
reduces the amplitude of the driving signal and can significantly increase the R
external high-side MOSFET and then its conductive loss.
CC
Figure 34.
. This voltage is obtained by means of an internal charge pump
BOOT
Vcc
. In the L6599 a patented integrated structure, replaces this external diode.
12
LVG
L6599
16
14
OUT
VBOOT
DS(on)
Application information
(Figure
BOOT
C
and the forward drop
BOOT
CC
(i.e. when the low
in case that the
34).
DS(on)
of the
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