YB1692 Datasheet, PDF (4/10 Pages) YOBON TECHNOLOGIES,INC. – 2A Synchronous Step-Down Converter

BLOCK DIAGRAM
YB1692
2A Synchronous Step-Down Converter
Figure 3
FUNCTIONAL DESCRIPTIONS
The YB1692 is a synchronous rectified, cur-
rent-mode,step-down regulator. It regulates
in- put voltages from 4.75V to 18V down to an
out- put voltage as low as 0.923V,and
supplies up to 2A of load current.
The YB1692 uses current-mode control to
regulate the output voltage. The output
voltage is measured at FB through a resistive
voltage di- vider and amplified through the
internal trans- conductance error amplifier.
The voltage at the COMP pin is compared to
the switch current measured internally to
control the output voltage.
The converter uses internal N-Channel
MOSFET switches to step-down the input
voltage to the regu- lated output voltage.Since
the high side MOSFET requires a gate
voltage greater than
the input voltage, a boost capacitor connected
between SW and BS is needed to drive the
high side gate. The boost capaci- tor is
charged from the internal 5V rail when SW is
low.
When the YB1692 FB pin exceeds 20% of the
nominal regulation voltage of 0.923V, the over
volt- age comparator is tripped and the COMP
pin and the SS pin are discharged to
GND,forcing the high-side switch off.
YB1692 Rev.1.0
www.yobon.com.tw
4