FUNCTIONAL DESCRIPTION
FUNCTIONAL INTERNAL BLOCK DESCRIPTION
Table 9. Serial Input Port Definition for DR1=DC Motor/DR2 =Step Mode
Reset
Value
Name
Bit
Description
1
1
1
1
0
V2_Enable
Enable bit to turn on and off the V2 regulator and the motor drivers and place the
34920 in the minimum power consumption state.
2
3
4
SDR2_CURR_I1_PHASEB
SDR2_CURR_I0_PHASEB
SDR2_DIR_PH_B
Second of two inputs that control the current level in the SDR2 step motor Phase
B winding.
One of two inputs that control the current level in the SDR2 step motor Phase B
winding.
Controls the direction of the current flow through Phase B of the SDR2 step motor.
A logic [1] level causes conventional current flow from PH_B+ (source) to PH_B+
(sink).
5
6
7
1
1
0
SDR2_CURR_I1_PHASEA
SDR2_CURR_I0_PHASEA
SDR2_DIR_PH_A
Second of two inputs that control the current level in the SDR2 step motor Phase
A winding.
One of two inputs that control the current level in the SDR2 step motor Phase A
winding.
Controls the direction of the current flow through Phase A of the SDR2 step motor.
A logic [1] level causes conventional current flow from PH_A+ (source) to PH_A-
(sink).
8
X
X
X
X
X
0
Not Used
Not used in this mode.
Not used in this mode.
Not used in this mode.
Not used in this mode.
Not used in this mode.
9
Not Used
10
11
12
13
Not Used
Not Used
Not Used
DR1_DIR_DCM
Controls the direction of the current flow through the DC motor. A logic [1] level
causes conventional current flow from DR1A1 (source)/DR1A2 (source) to DR1B1
(sink)/DR1B2 (sink).
VVB+, the input voltage for the switching voltage
VOLTAGE REGULATORS
regulators, ranges from 21 V to 42 V. To minimize the ripple
current on VVB+, the V1 regulator and the V2 regulator switch
The 34920 contains two switching voltage regulators (see
Figure 6). Both are buck-type voltage regulators using an
internal switching MOSFET. The V1 regulator provides either
3.3 V or 5.0 V at +5%/-4% tolerance. The V2 regulator’s
output voltage, VV2, is programmable through the use of an
out of phase.
A boost voltage generator (VB generator), which acts as a
single-stage charge pump, provides gate drive voltage for the
switching regulators. It uses an external capacitor to store the
charge.
external resistor divider network. The voltage tolerance on
the VV2 output is ±2% of the nominal voltage set point. The
switching frequency of the V1 and V2 regulators is
approximately 200 kHz.
Output voltages VV1 and VV2 are set externally with a
resistor (1% tolerance) divider network. Input voltages at
V1_FB and V2_FB should be chosen to provide a feedback
voltage, for the required output regulated voltage, to equal
the internal regulator reference voltages of 2.5 V ±2%.
The V1 and V2 regulators are designed with a dual-mode
current limit circuit. The current limit threshold is lowered
during the power-on period to allow for a softer start-up,
thereby reducing electrical stress in the external
components.
34920
Analog Integrated Circuit Device Data
Freescale Semiconductor
17
FREESCALE [ Freescale ]
