Circuit Description - ViewSonic VP191b-1 Service Manual

4. Circuit Description

1. Power supply (DC/DC Converter)
The AP1501 is monolithic IC designed for M/B DC/DC converter, with the ability of driving a 3A load without any
additional transistor component.
The AP1501 operates at a switching frequency of 150 kHz and thus allows smaller-sized filter components than
would be needed with lower frequency switch regulator.
2. Flash Memory
The Pm39LV010R is a 1 Megabit, 3.3 Volt-only Flash Memory organized as 131,072 bytes of 8 bits each. This device is
designed to use a 3.0 Volt to 3.6 Volt power supply to perform in-system programming.
The 1 Megabit memory array is divided into thirty-two uniform blocks of 4 Kbytes each for data and/or code storage.
The block architecture allows users to flexibly make chip erase or block erase operation. The block erase feature allows a
particular block to be erased and reprogrammed without affecting the data in other blocks. After the device performs chip
erase or block erase operation, it can be reprogrammed on a byte-by-byte basis.
Confidential - Do Not Copy
ViewSonic Corporation VP191b/s
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