SLVSEC9C September 2019 – February 2020 DRV8904-Q1 , DRV8906-Q1 , DRV8908-Q1 , DRV8910-Q1 , DRV8912-Q1
PRODUCTION DATA.
The half-bridges are configured to operate in the continuous mode without using any PWM switching by default. Any high-side or low-side switch is switched on by individually setting the high-side enable bits (HBX_HS_EN) and low-side enable bits (HBX_LS_EN) in operation control registers (OP_CTRL_1, OP_CTRL_2 and OP_CTRL_3).
NOTE
If the high-side enable bit (HBX_HS_EN) and low-side enable bit (HBX_LS_EN) of a particular half-bridge is set high (shoot-through configuration), then the particular half-bridge driver will remain in Hi-Z state until he shoot-through condition is cleared.
The high-side and low-side enable bits of a particular half-bridge are configured to drive the motor in forward mode, reverse mode, brake mode and coast mode as shown in Table 2.
nSLEEP | HALF-BRIDGE-1 | HALF-BRIDGE-2 | OUT1 | OUT2 | BRIDGE OPERATION
(DC MOTOR) |
---|---|---|---|---|---|
0 | HB1_HS_EN = Don't Care
HB1_LS_EN = Don't Care |
HB2_HS_EN = Don't Care
HB2_LS_EN = Don't Care |
Z | Z | Sleep Mode |
1 | HB1_HS_EN = 0
HB1_LS_EN = 0 |
HB2_HS_EN = 0
HB2_LS_EN = 0 |
Z | Z | Motor Coast |
1 | HB1_HS_EN = 1
HB1_LS_EN = 0 |
HB2_HS_EN = 0
HB2_LS_EN = 1 |
H | L | Forward Direction |
1 | HB1_HS_EN = 0
HB1_LS_EN = 1 |
HB2_HS_EN = 1
HB2_LS_EN = 0 |
L | H | Reverse Direction |
1 | HB1_HS_EN = 0
HB1_LS_EN =1 |
HB2_HS_EN = 0
HB2_LS_EN = 1 |
L | L | Motor Brake (Low-Side) |
1 | HB1_HS_EN =1
HB1_LS_EN = 0 |
HB2_HS_EN = 1
HB2_LS_EN = 0 |
H | H | Motor Brake (High-Side) |
1 | HB1_HS_EN = 1
HB1_LS_EN = 1 |
HB2_HS_EN = 1
HB2_LS_EN = 1 |
Z | Z | Motor Coast |
Figure 30 shows the bridge configuration for motor operation in forward direction with high-side FET of OUT1 and low-side FET of OUT2 in conducting state with current flowing from OUT1 to OUT2. Similarly, the motor operation in reverse direction is achieved by switching ON the high-side FET of OUT2 and low-side FET of OUT1 such that current flows from OUT2 to OUT1 as shown in Figure 31.
Figure 32 and Figure 33 shows the bridge operation in coast mode with motor initially running in forward and reverse direction respectively. As shown in these figures, due to the energy stored in motor's inductance, the current will continue to flow in motor and take the path flow through the body diodes of FETs.
Figure 34 shows the low-side braking of the motor when both low-side FET's of the driver are turned ON. In this case, the motor is considered to be operating in forward direction (current flow from OUT1 to OUT2) and then braking is applied. similarly, for the high-side braking, both high-side FET's of the driver are turned ON as shown in Figure 35.