L6591 STMicroelectronics, L6591 Datasheet - Page 23

• Manufacturer Part Number: L6591
• Description: IC CTRLR PWM PROG CM HV 16SOIC
• Manufacturer: STMicroelectronics

Specifications of L6591

• Output Isolation: Isolated
• Frequency Range: 168 ~ 192kHz
• Voltage - Input: 8.7 ~ 22 V
• Power (watts): 750mW
• Operating Temperature: -40°C ~ 150°C
• Package / Case: 16-SOIC (0.154", 3.90mm Width)
• Output Voltage: 5 V
• Input Voltage: 25 V
• Operating Temperature Range: - 40 C to + 150 C
• Mounting Style: SMD/SMT
• Duty Cycle (max): 50 %
• For Use With: 497-8335 - BOARD EVAL FOR L6591
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 497-8286

L6591
Figure 41. Timing diagram: normal power-up and power-down sequences
At converter power-down the system will lose regulation as soon as the input voltage is so
low that either peak current or maximum duty cycle limitation is tripped. Vcc will then drop
and stop IC’s activity as it falls below the UVLO threshold (10.5 V typ.). The Vcc_OK signal
is de-asserted as the Vcc voltage goes below a threshold Vcc
HV generator can now restart but, if Vin < Vin
asserted too and the HV generator is disabled. This prevents converter’s restart attempts
and ensures monotonic output voltage decay at power-down.
The low restart threshold Vcc
the L6591 will have a very low repetition rate, as shown in the timing diagram of
and that the converter will work safely with extremely low power throughput.
The restart threshold of the HV generator is changed when any latched disable function of
the IC is invoked to ensure a real latch-off. For more details see “Latched shutdown” section.
PFC_STOP
HVG, LVG
Vcc_OK
Vcc
HV_EN
I
0.75 mA
ch arg e
VH
Vcc
Vcc
res tart
Vcc
Vi n
s tart
on
off
Power-on
rest
Doc ID 14821 Rev 5
ensures that, during short circuits, the restart attempts of
start
operation
, as shown in
Normal
rest
Figure
located at about 5 V. The
Application information
Power-off
41, HV_EN is de-
regulation is lost here
Figure
23/41
t
t
t
t
t
t
42,