DS75LVU+T&R【PDF 6/13 页】IC SENSOR TEMP DIGITAL 8MSOP

收藏本站

您好，
买卖IC网欢迎您。
请登录
免费注册

买卖IC网

Sheet目录40

2页 3页 4页 5页 [6页]7页 8页 9页 10页

DS75LV: Digital Thermometer and Thermostat

6 of 13

OPERATION?/SPAN>THERMOSTAT

The DS75LV thermostat has two operating modes, comparator mode and interrupt mode, which activate and

deactivate the open-drain thermostat output (O.S.) based on user-programmable trip-points (T

and T

HYST

). The

DS75LV powers up with the thermostat in comparator mode, active-low O.S. polarity, over-temperature trip-point

) register set to 80C, and the hysteresis trip-point (T

HYST

) register set to 75篊. If these power-up settings are

compatible with the application, the DS75LV can be used as a standalone thermostat (i.e., no 2wire

communication required). If interrupt mode operation, active-high O.S. polarity or different T

and T

HYST

values are

desired, they must be programmed after power-up, so standalone operation is not possible.

In both operating modes, the user can program the thermostat fault tolerance, which sets how many consecutive

temperature readings (1, 2, 4, or 6) must fall outside of the thermostat limits before the thermostat output is

triggered. The fault tolerance is set by the F1 and F0 bits in the configuration register. At power-up the fault

tolerance is set to 1.

The data format of the T

and T

HYST

registers is identical to that of the temperature register (see Figure 3), i.e., a

two-byte twos complement representation of the trip-point temperature in degrees centigrade with bits 3 through 0

hardwired to 0. After every temperature conversion, the measurement is compared to the values stored in the T

and T

HYST

registers. The O.S. output is updated based on the result of the comparison and the operating mode of

the IC. The number of T

and T

HYST

bits used during the thermostat comparison is equal to the conversion

resolution set by the R1 and R0 bits in the configuration register. For example, if the resolution is 9 bits, only the 9

MSbs of T

and T

HYST

will be used by the thermostat comparator.

The active state of the O.S. output can be changed via the POL bit in the configuration register. The power-up

default is active low.

If the user does not wish to use the thermostat capabilities of the DS75LV, the O.S. output should be left floating.

Note that if the thermostat is not used, the T

and T

HYST

registers can be used for general storage of system data.

Comparator Mode: When the thermostat is in comparator mode, O.S. can be programmed to operate with any

amount of hystoresis. The O.S. output becomes active when the measured temperature exceeds the T

value a

consecutive number of times as defined by the F1 and F0 fault tolerance (FT) bits in the configuration register. O.S.

then stays active until the first time the temperature falls below the value stored in T

HYST

. Putting the device into

shutdown mode does not clear O.S. in comparator mode. Thermostat comparator mode operation with FT = 2 is

illustrated in Figure 4.

Interrupt Mode: In interrupt mode, the O.S. output first becomes active when the measured temperature exceeds

the T

value a consecutive number of times equal to the FT value in the configuration register. Once activated,

O.S. can only be cleared by either putting the DS75LV into shutdown mode or by reading from any register

(temperature, configuration, T

, or T

HYST

) on the device. Once O.S. has been deactivated, it will only be

reactivated when the measured temperature falls below the T

HYST

value a consecutive number of times equal to the

FT value. Again, O.S can only be cleared by putting the device into shutdown mode or reading any register. Thus,

this interrupt/clear process is cyclical between T

and T

HYST

events (i.e, T

, clear, T

HYST

, clear, T

HYST

clear, etc.). Thermostat interrupt mode operation with FT = 2 is illustrated in Figure 4.

发布紧急采购，3分钟左右您将得到回复。

采购需求

(若只采购一条型号，填写一行即可)

*型号	*数量	厂商	批号	封装

添加更多采购

采购需求

发布成功！您可以继续发布采购。也可以进入我的后台，查看报价

发布成功！您可以继续发布采购。也可以进入我的后台，查看报价

我的联系方式