BD9610AMUV-E2 Datasheet, PDF (3/30 Pages) Rohm – 60V Synchronous Step-down Switching Regulator(Controller type)

BD9610AMUV
●Block Functional Description
1. 5VREG
5V Regulator supplied voltage for Internal Circuits(5V±2%).
It is available as external supply voltage for current ability (2mA Max) or less.
2. ERROR AMP
Error amplifier output PWM control signal after detected output signal.
Internal reference voltage is 0.8V(accuracy±1%).
Connect capacitor and resistor between inverting pin (INV) and output pin (FB) as phase compensation elements.
3. Soft Start
A Circuit that does Soft Start to the Output Voltage of DC／DC Comparator, and prevents Rush Current during
start-up. The external capacitor of SS pin is charged with the internal source current (1uA), and That slope inputs to
the error amplifier as the reference voltage of the start-up.
4. OSC
This is a oscillator for the reference of the PWM modulation. The frequency of the internal triangle wave is
programmed by RRT which connected to RT within 50kHz to 500kHz. RT pin is the output of the buffer
of RTSS voltage. CLKOUT is the output of the internal oscillator as the square wave.
Also this can be synchronized to an external clock through the SYNC pin.
5. PWMCOMP
This is a comparator for PWM modulation comparing the output of error amplifier and ramp wave
to decide switching duty. Switching duty is limited by HG min OFF time(350ns),
because of charging of BST-LX capacitor.
6. DRV
It drives the external FETs. Particularly, high side DRV is built in UVLO.
7. 10VREG
10V Regulator supplied voltage for low-side driver and charged capacitor between BST and LX through
internal switch.
8. UVLO
This is a Low Voltage Error Prevention Circuit.
This prevents internal circuit error during increase of Power supply Voltage and during decline of Power supply
voltage. It monitors VCC, REG5 and REG10. This operation turns off both external FET and reset soft-start
by detecting the monitoring voltage under each threshold.
9. TSD
This is a heat protect (Thermal Shut Down) circuit.
When it detects an abnormal temperature exceeding Maximum Junction Temperature (Tj=150℃), it turns off
both external FET. It has with Hysteresis and automatically releases by becoming under the threshold temperature.
10. OCP
This is a Over Current Protection circuit. It uses a two-tier approach. The first tier is a pulse-by-pulse protection
scheme. Current limit is implemented on the high-side FET by sensing the CLH-CLL voltage when the gate is driven
high. The CLH-CLL voltage is compared to the threshold voltage programmed by RCL resister. If the CLH-CLL
voltage exceeds the threshold, the switching pulse is immediately terminated. The FET remains off until the next
switching cycle is initiated. The second consists of a fault counter. The fault counter is incremented on
an over-current pulse. When the counter reaches two within three pulse, both FETs, FB and SS are tuned off
during the definite time. After the time both FET, FB and SS are released, and automatically re-start with soft-start.
11. CTL
With the voltage applied to CTL, IC ON／OFF can be controlled.
When a voltage of 2.8V or more is applied, it turns ON, at open or 0V application, it turns OFF.
About 300kΩ pull-down resistance is contained within the pin.
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TSZ02201-0Q1Q0AJ00010-1-2
24.OCT.2014 Rev.002