Datasheet

DocID15567 Rev 6 25/53
L99H01 Device description
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3 Device description
3.1 Dual power supply: V
S
and V
CC
The power supply voltage V
S
supplies the charge-pump. An internal charge-pump is used to
drive the high-side switches and the low-side switches. The logic supply voltage V
CC
(3.3 V / 5 V) is used for the logic part and the SPI of the device. Due to the independent logic
supply voltage the control and status information is not lost, even if the supply voltage V
S
is
switched-off. In case of power-on (V
CC
increases from undervoltage to
V
POR OFF
= 2.5 V, typical) the circuit is initialized by an internally generated power-on reset
(POR). If the voltage V
CC
decreases under the minimum threshold (V
POR ON
=2.2V,
typical), the outputs are switched-off and the status registers are cleared.
3.2 Standby mode (EN)
The L99H01 is activated with enable input high signal. For enable input floating (not
connected) or V
EN
= 0 V the device is in standby mode. All latched data are cleared and the
inputs and outputs are switched-off. In the standby mode the current at V
S
is less than 5 µA
(1 µA) for CSN = high (DO in tristate). If V
CC
> V
POR OFF
and EN = high the device enters
the active mode. In the active mode the charge-pump and the diagnostic functions are
active.
3.3 H-bridge control (DIR, PWM, bit FW)
The DIR and PWM inputs control the drivers of the external H-bridge transistors. The motor
direction can be chosen with the DIR input, the duty cycle and frequency with the PWM
input. With the SPI registers FW and FW-PAS 4 different free wheeling modes (2 active and
2 passive) can be selected using the high-side transistors or the low-side transistors.
Unconnected inputs are defined by internal pull-down current.