IC CTRLR PWM 1PHASE SO-8

L6726A

Manufacturer Part NumberL6726A
DescriptionIC CTRLR PWM 1PHASE SO-8
ManufacturerSTMicroelectronics
TypeStep-Down (Buck)
L6726A datasheet
 


Specifications of L6726A

Internal Switch(s)NoSynchronous RectifierNo
Number Of Outputs1Voltage - OutputAdj to 0.8V
Frequency - Switching270kHzVoltage - Input1.5 ~ 12 V
Operating Temperature-20°C ~ 85°CMounting TypeSurface Mount
Package / Case8-SOIC (3.9mm Width)Output Current1.5 A
Input Voltage4.1 V to 13.2 VOperating Temperature Range- 40 C to + 150 C
Mounting StyleSMD/SMTFor Use With497-9046 - BOARD EVAL BASED ON L6726A497-6364 - BOARD DEMO FOR TS4995EIJT497-6259 - BOARD EVAL 1PH STPDN CONV L6726A
Lead Free Status / RoHS StatusLead free / RoHS CompliantCurrent - Output-
Power - Output-  
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Soft start and disable
6
Soft start and disable
L6726A implements a soft start to smoothly charge the output filter avoiding high in-rush
currents to be required from the input power supply. The device sources a 10 µA soft start
current from COMP, linearly charging the compensation network capacitors. The ramping
COMP voltage is compared to the oscillator triangular waveform generating PWM pulses of
increasing width that charge the output capacitors.
When the FB voltage crosses 800 mV, the output voltage is in regulation: soft start phase
will end and the transconductance error amplifier output will be enabled closing the control
loop.
In the event of an over current during soft start, the over current logic will override the soft
start sequence and will shut down the PWM logic and both the high side and low side gates.
This condition is latched, cycle VCC to recover.
The device sources soft start current only when VCC power supply is above UVLO
threshold and over current threshold setting phase has been completed.
6.1
Low-side-less start up (LSLess)
L6726A performs a special sequence in enabling LS driver to switch: during the soft-start
phase, the LS driver results disabled (LS = OFF) until the HS starts to switch. This avoids
the dangerous negative spike on the output voltage that can happen if starting over a pre-
charged output and limits the output discharge (amount of output discharge depends on
programmed SS time length: the shorter the programmed SS, the more limited the output
discharge).
If the output voltage is pre-charged to a voltage higher than the final one, the HS would
never start to switch. In this case, LS is enabled and discharges the output to the final
regulation value.
Figure 5.
LSLess startup (left) vs non-LSLess startup (right)
6.2
Enable / disable
The device can be disabled by pushing COMP / DIS pin under 0.4 V (min). In this condition
HS and LS MOSFETs are turned off, and the 10
pin. Setting free the pin, the device enables again performing a new SS.
12/35
μ
A SS current is sourced from COMP / DIS
Doc ID 12754 Rev 4
L6726A