DS2720BU データシートの表示（PDF） - Dallas Semiconductor -> Maxim Integrated

部品番号

コンポーネント説明

メーカー

DS2720BU

Efficient, Addressable Single-Cell Rechargeable Lithium Protection IC

Dallas Semiconductor -> Maxim Integrated 

DS2720

SPECIAL FEATURE REGISTER

The format of the special feature register is shown in Figure 7. The function of each bit is described in

detail in the following paragraphs.

Figure 7. SPECIAL FEATURE REGISTER FORMAT

Bit 7

PSF

Bit 6

X

Bit 5

X

Address 08

Bit 4 Bit 3

X

X

Bit 2

X

Bit 1

X

Bit 0

OT

PSF— PS Flag. This bit is reset to 0 when the DS2720 detects the PS pin is pulled to VSS. This bit does

not set itself to a 1 after the PS pin returns to a high logic level, and thus must be set by the host system

to detect future events. This bit is initialized to a 1 upon POR.

OT—Overtemperature Flag. When set to 1, this bit indicates the battery pack has experienced an

overtemperature condition. This bit does not clear itself after the overtemperature state is corrected, and

thus must be reset by the host system after the temperature decreases below TMAX to re-enable the charge

and discharge FETs. Writing a 1 to this bit disables the FETs, but this is not recommended. The OT bit is

a volatile R/W bit, initialized to 0 upon POR.

X—Reserved Bits.

PS INPUT PIN

The PS pin is internally pulled to VDD through a high-value resistance. PS is continuously monitored for

a low-impedance connection to VSS. Connecting PS to VSS wakes up the DS2720 if it was in sleep mode.

If the DS2720 was in active mode, PS has no effect.

1-WIRE BUS SYSTEM

The 1-Wire bus is a system that has a single bus master and one or more slaves. A multidrop bus is a 1-

Wire bus with multiple slaves. A single-drop bus has only one slave device. In all instances, the DS2720

is a slave device. The bus master is typically a microprocessor in the host system. The discussion of this

bus system consists of four topics: 64-bit net address, hardware configuration, transaction sequence, and

1-Wire signaling.

64-BIT NET ADDRESS

Each DS2720 has a unique, factory-programmed 1-Wire net address that is 64 bits in length. The first

eight bits are the 1-Wire family code (31h for DS2720). The next 48 bits are a unique serial number. The

last eight bits are a CRC of the first 56 bits (see Figure 8). The 64-bit net address and the 1-Wire I/O

circuitry built into the device enable the DS2720 to communicate through the 1-Wire protocol detailed in

the 1-Wire Bus System section of this data sheet.

11 of 21

Share Link: