L9949 datasheet(3/20 Pages) STMICROELECTRONICS

3 / 20 page

3/20

L9949

Temperature Warning and Thermal Shutdown

When the junction temperature rises above Tj TW a temperature warning flag is set and is available via the SPI.

If the junction temperature increases above the second threshold Tj SD, the thermal shutdown bit will be set and

the power DMOS transistors of the output stages are switched off to protect the device. In order to reactivate

the output stages the junction temperature must decrease below Tj SD - Tj SD HYS and the thermal shutdown bit

has to be cleared by the microcontroller.

Open Load Detection

The open load detection monitors the voltage drop of current sense resistors in each highside and lowside driver

of the output stage. The output signal of an open load comparator has to be valid for at least 0.5 ms (tdOL) to

set the open load bit (bit 1-11) in the status register 1.

Over Load Detection

In the case of an overcurrent condition an overcurrent flag (bit 1-11) is set in the status register 0 in the same

way as open load detection. If the overcurrent signal is valid for at least tISC = 10µs, the overcurrent flag is set

and the corresponding driver is switched off to reduce the power dissipation and to protect the integrated circuit.

The microcontroller has to clear the status bits to reactivate the corresponding driver.

Current monitor

The current monitor output sources a current image at the current monitor output which has a fixed ratio (1/

10000) of the instantaneous current of the selected highside driver. The bits 12 and 13 of the Input Data register

controls which of the outputs OUT1, OUT2 and OUT6 will be multiplexed to the current monitor output. The cur-

rent monitor output allows a more precise analyse of the actual state of the load rather than the detection of an

open- or overload condition. For example this can be used to detect the motor state (free-running, loaded or

blocked) or the temperature of the heating element.

Figure 1. Pin Connection (Top view)

GND

OUT1

CLK

OUT5

OUT4

OUT3

OUT6

VCC

CSN

OUT2

GND

D99AT455Amod

L9949 数据表(PDF) 3 Page - STMicroelectronics

L9949 数据表(HTML) 3 Page - STMicroelectronics

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

数据表下载