E-L6202 Datasheet, PDF (10/20 Pages) STMicroelectronics – DMOS FULL BRIDGE DRIVER

L6201 - L6202 - L6203
CIRCUIT DESCRIPTION
The L6201/1PS/2/3 is a monolithic full bridge
switching motor driver realized in the new Mul-
tipower-BCD technology which allows the integra-
tion of multiple, isolated DMOS power transistors
plus mixed CMOS/bipolar control circuits. In this
way it has been possible to make all the control
inputs TTL, CMOS and µC compatible and elimi-
nate the necessity of external MOS drive compo-
nents. The Logic Drive is shown in table 1.
Figure 15: Current Typical Spikes on the Sens-
ing Pin
Table 1
Inputs
IN1
L
V_EN = H
L
H
H
V_EN = L
X
Output Mosfets (*)
IN2
L Sink 1, Sink 2
H Sink 1, Source 2
L Source 1, Sink 2
H Source 1, Source 2
X All transistors turned oFF
L = Low
H = High
X = DON’t care
(*) Numbers referred to INPUT1 or INPUT2 controlled output stages
Although the device guarantees the absence of
cross-conduction, the presence of the intrinsic di-
odes in the POWER DMOS structure causes the
generation of current spikes on the sensing termi-
nals. This is due to charge-discharge phenomena
in the capacitors C1 & C2 associated with the
drain source junctions (fig. 14). When the output
switches from high to low, a current spike is gen-
erated associated with the capacitor C1. On the
low-to-high transition a spike of the same polarity
is generated by C2, preceded by a spike of the
opposite polarity due to the charging of the input
capacity of the lower POWER DMOS transistor
(fig. 15).
Figure 14: Intrinsic Structures in the POWER
DMOS Transistors
TRANSISTOR OPERATION
ON State
When one of the POWER DMOS transistor is ON
it can be considered as a resistor RDS (ON)
throughout the recommended operating range. In
this condition the dissipated power is given by :
PON = RDS (ON) ⋅ IDS2 (RMS)
The low RDS (ON) of the Multipower-BCD process
can provide high currents with low power dissipa-
tion.
OFF State
When one of the POWER DMOS transistor is
OFF the VDS voltage is equal to the supply volt-
age and only the leakage current IDSS flows. The
power dissipation during this period is given by :
POFF = VS ⋅ IDSS
The power dissipation is very low and is negligible
in comparison to that dissipated in the ON
STATE.
Transitions
As already seen above the transistors have an in-
trinsic diode between their source and drain that
can operate as a fast freewheeling diode in
switched mode applications. During recirculation
with the ENABLE input high, the voltage drop
across the transistor is RDS (ON) ⋅ ID and when it
reaches the diode forward voltage it is clamped.
When the ENABLE input is low, the POWER
MOS is OFF and the diode carries all of the recir-
culation current. The power dissipated in the tran-
sitional times in the cycle depends upon the volt-
age-current waveforms and in the driving mode.
(see Fig. 7ab and Fig. 8abc).
Ptrans. = IDS (t) ⋅ VDS (t)
10/20