L6725 STMicroelectronics, L6725 Datasheet - Page 15

• Manufacturer Part Number: L6725
• Description: IC CTRLR PWM W/BOOTSTRAP SO-16N
• Manufacturer: STMicroelectronics

Specifications of L6725

• Pwm Type: Voltage Mode
• Number Of Outputs: 1
• Frequency - Max: 550kHz
• Duty Cycle: 100%
• Voltage - Supply: 4.5 V ~ 18 V
• Buck: Yes
• Boost: No
• Flyback: No
• Inverting: No
• Doubler: No
• Divider: No
• Cuk: No
• Isolated: No
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 16-SOIC (3.9mm Width)
• Frequency-max: 550kHz
• Package: SO16N
• For Use With: 497-5867 - EVAL BOARD 20A 250KHZ L6725497-5500 - EVAL BOARD FOR L6725
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

L6725 - L6725A
5.9
Figure 9.
5.10
Hiccup mode
During the soft-start phase the OCP provides a constant-current-protection. If during the T
the OCH comparator triggers an over current the high-side MOSFET(s) is immediately turned
OFF (after the masking time and the internal delay) and returned on at the next pwm cycle. The
limit of this protection is that the T
because during the masking time the peak-current-protection is disabled. In case of very hard
short circuit, even with this short T
is very helpful in this case to limit the current. If during the off-time the OCL comparator triggers
an over current, the high-side MOSFET(s) is not turned on until the current is over the valley-
current-limit. This implies that, if it is necessary, some pulses of the high-side MOSFET(s) will
be skipped, guaranteeing a maximum current due to the following formula:
Thermal shutdown
When the junction temperature reaches 150°C ±10°C the device enters in thermal shutdown.
Both MOSFETs are turned OFF and the soft-start capacitor is rapidly discharged with an
internal switch. The device does not restart until the junction temperature goes down to 120°C
and, in any case, until the voltage at the soft-start pin reaches 500mV.
Constant current and Hiccup Mode during an OCP.
I
MAX
=
I
VALLEY
ON
ON
+
cannot be less than masking time plus propagation delay,
, the current could escalate. The valley-current-protection
Vin
−
L
Vout
⋅
T
ON
,
MIN
(1)
VSS
Device description
VCOMP
I
L
15/32
ON