MTS2916A-LGC1 Microchip Technology, MTS2916A-LGC1 Datasheet - Page 9

• Manufacturer Part Number: MTS2916A-LGC1
• Description: Dual Full-Bridge PWM Motor Driver 24 SOIC .300in T/R
• Manufacturer: Microchip Technology
• Type: Dual Full-Bridge Motor Driverr

Specifications of MTS2916A-LGC1

• Product: Stepper Motor Controllers / Drivers
• Operating Supply Voltage: 10 V to 40 V
• Supply Current: 0.8 mA
• Mounting Style: SMD/SMT
• Package / Case: SOIC-24
• Operating Temperature: - 20 C to + 85 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

3.2
The current level in each motor winding is controlled by
a PWM circuit with a fixed T
flowing in the winding is sensed through an external
sensing resistor Rs connected between the power
bridge's source pin SENSE (sources of transistors Na
and Nb) and GND.
FIGURE 3-2:
The voltage across Rs is compared to a fraction of the
reference voltage VREF, chosen with the logic input
bits I0 and I1
the load current can also be switched off completely
when both logic inputs are high. Note that any logic
input left unconnected will be treated as a high level
(pull-up resistor).
The maximum trip current for regulation, given for I0 I1
= 00 is calculated in
TABLE 3-3:
When the maximum allowed current is reached, the
bridge source is turned off during a fixed period T
(typically 50us) given by a non-retriggerable pulse gen-
erator and the external timing components Rt (20k-
100 k range) and Ct (100 pF-1000 pF range):
toff = 1.1*(Rt*Ct)
 2010 Microchip Technology Inc.
PWM Current Control
VREF
I0
0
1
0
1
I0
I1
(Table
CURRENT LEVEL CONTROL TRUTH TABLE
Equation
3-3). The power bridge and thus
PWM Current Control Circuit Principle (Channel 1 Shown)
OFF
3-1.
COMPIN
time. The load current
Cc
÷10
I1
0
0
1
1
Rc
OFF
RC
Ct
One-Shot
Comp. Trip Voltage
Vtrip = 1/10*Vref
Vtrip = 1/15*Vref
Vtrip = 1/30*Vref
EQUATION 3-1:
During T
driver is re-enabled, the winding current increases
again until it reaches the threshold, and the cycle
repeats itself maintaining the load current at the desired
level.
Rt
Source
Disable
Power
Bridge
x
OFF,
Pa
Na
the winding current decreases. When the
VLOAD
I
MAX
SENSE
Rs

MTS2916A
10
Pb
Nb
2/3*Imax = Vref/15RS
1/3*Imax = Vref/30RS
V
Imax = Vref/10RS
REF
*
Output Current
0 (no current)
R
S
OUTA
OUTB
DS22259A-page 9