Teclast X21, Руководство по обслуживанию

Страница: 55 / 76

Pin function is shown as the following figure
：
Pin Contiguous signal name Function description
9 /CE Chip selection
8 /RE Read gating
18 /WE Write gating
19 /WP Write protection
7 RY/BY Busy/idle judgment
12
、
37
VCC Power supply
3.5.5 Function introduction to SI1912DL
SI1912DL integrates 2 MOS tubes insides and is used to control on/off of two circuits. In X17 (RU),it is
served as control IC of secondary output.
Pin function is shown as the following figure
：
Pin Contiguous signal name Function description
1 S1 S electrode of MOS tube 1
2 D1 D electrode of MOS tube 1
3 G2 G electrode of MOS tube 2
4 S2 S electrode of MO tube 2
5 G2 G electrode of MOS tube 2
6 D1 D electrode MO tube 1
3.5.6 Function introduction to LM2703
The LM2703 is a micropower step-up DC/DC in a small 5-lead SOT-23 package. A current limited, fixed
off-time control scheme conserves operating current resulting in high efficiency over a wide range of load
conditions. The 21V switch allows for output voltages as high as 20V. The low 400ns off-time permits the use
of tiny, low profile inductors and capacitors to minimize footprint and cost in space-conscious portable
applications. The LM2703 is ideal for LCD panels requiring low current and high efficiency as well as white
LED applications for cellular phone back-lighting. The LM2703 can drive up to 4 white LEDs from a single
Li-Ion battery.
- 50 -