DRV8828_15 Datasheet, PDF (9/21 Pages) Texas Instruments – H-BRIDGE MOTOR CONTROLLER IC

DRV8828
www.ti.com
SLVSA11F – OCTOBER 2009 – REVISED DECEMBER 2013
The full-scale (100%) chopping current is calculated in Equation 1.
V
I = ₅^¾ _{R CHOP}
REFX
· _ISENSE
(1)
Example:
If a 0.5-Ω sense resistor is used and the VREFx pin is 3.3 V, the full-scale (100%) chopping current will be
3.3 V / (5 x 0.5 Ω) = 1.32 A.
Five input pins (I0 - I4) are used to scale the current in the bridge as a percentage of the full-scale current set by
the VREF input pin and sense resistance. The logic inputs I0, I1, I2, I3 and I4 have internal pulldown resistors of
100 kΩ. The function of the pins is shown in Table 3.
Table 3. H-Bridge Pin Functions
I[4..0]
0x00h
0x01h
0x02h
0x03h
0x04h
0x05h
0x06h
0x07h
0x08h
0x09h
0x0Ah
0x0Bh
0x0Ch
0x0Dh
0x0Eh
0x0Fh
0x10h
0x11h
0x12h
0x13h
0x14h
0x15h
0x16h
0x17h
0x18h
0x19h
0x1Ah
0x1Bh
0x1Ch
0x1Dh
0x1Eh
0x1Fh
RELATIVE CURRENT
(% FULL-SCALE CHOPPING CURRENT)
0%
5%
10%
15%
20%
24%
29%
34%
38%
43%
47%
51%
56%
60%
63%
67%
71%
74%
77%
80%
83%
86%
88%
90%
92%
94%
96%
97%
98%
99%
100%
100%
Decay Mode
During PWM current chopping, the H-bridge is enabled to drive current through the motor winding until the PWM
current chopping threshold is reached. This is shown in Figure 2 as case 1. The current flow direction shown
indicates the state when the PHASE pin is high.
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