Inverse Operation Behavior
of the BTS6143 and its family members
Abstract
1
Abstract
Note: The following information is given as a hint for the implementation of the device only and shall not be
regarded as a description or warranty of a certain functionality, condition or quality of the device.
This Application Note provides information about the specific behavior of the BTS6143D and its family members
for the special operation mode “inverse operation”.
The application note describes first the specific characteristics of the BTS6143D and its family members. It
describes the special operation mode “inverse operation”. It outlines the behavior of the BTS6143D diagnosis and
power stage and provides background information for the special behavior. Finally this application note provides
further information regarding the impact of inverse operation effects and provides hints for possible counter
measures on device and system level.
In the following all information is given and explained based on the product BTS6143D. However the outlined
information is also valid for all family members which utilize the same features and therefore show the same
behavior.
2
Introduction
The BTS6143D is a member of a very scalable and flexible family of high current high side switches. It provides
embedded protection functions and diagnosis. The embedded device functionality targets an optimum
compromise between application requirements and device capabilities.
2.1
Specific characteristics of the BTS6143D and its family members
The BTS6143D provides current sense functionality. A dedicated pin IS supports the monitoring of the load current
whenever the device is commanded ON.
The current sense capability of the BTS6143D and its family members targets the monitoring of the load current
across a very wide range. A special functionality has been implemented to extend the load current monitoring
capability towards very low load current values. This additional functionality dramatically improves the load current
monitoring capability at low load currents. However it can cause some side effects at non-normal operation
conditions.
The implemented measure for improved load current monitoring utilizes a special functionality called “Gate-Rück-
Regelung” (short GRR) or “Output voltage drop limitation” (short OVDL). The functionality output voltage drop
limitation increases significantly the current sense capability and accuracy at low load currents. This is achieved
by limiting the voltage drop across the power stage to a defined value of +V
ON(NL)
at low load currents (for details
see also the individual product data sheet). However, OVDL is also root cause for the following explained side
effects.
2.2
Inverse operation
The BTS6143D and its family members is used to switch the positive supply rail +V
S
of a battery feed to the load.
Figure 1
shows a typical application example.
Application Note
2
V1.1, 2008-03-31