High Current PN Half Bridge
BTS 7970B
Block Description and Characteristics
4.2
Power Stages
The power stages of the BTS 7970B consist of a p-channel vertical DMOS transistor for
the high side switch and a n-channel vertical DMOS transistor for the low side switch. All
protection and diagnostic functions are located in a separate top chip. Both switches can
be operated up to 25 kHz, allowing active freewheeling and thus minimizing power
dissipation in the forward operation of the integrated diodes.
The on state resistance RON is dependent on the supply voltage VS as well as on the
junction temperature Tj . The typical on state resistance characteristics are shown in
Figure 6.
High Side Switch
25
mΩ
20
RON(HS)
15
Low Side Switch
25
mΩ
20
RON(LS)
15
Tj = 150°C
10
5
4
Figure 6
Tj = 150°C
Tj = 25°C
Tj = -40°C
8 12 16 20 24 V 28
VS
10
5
4
Tj = 25°C
T j = -40°C
8
12
16 20 24 V 28
VS
Typical On State Resistance vs. Supply Voltage
Data Sheet
9
Rev. 2.0, 2006-05-09