TLE8242-2 Datasheet, PDF (18/78 Pages) Infineon Technologies AG – 8 Channel Fixed Frequency Constant Current Control With Current Profile Detection

TLE8242-2
Functional Description and Electrical Characteristics
5.2
Input / Output
All digital inputs are compatible with 3.3 V and 5 V I/O logic levels. The supply voltage for the SPI output SO is the
V_SIGNAL pin. All digital inputs are pulled to a known state by a weak internal current source or current sink when
not connected. However, unused digital input pins should be connected to ground or to V_SIGNAL (according to
the desired functionality) by an external connection or resistor. All input pin weak internal current sources are
supplied by the V_SIGNAL pin.
The RESET_B pin is an active low input pin. When this pin is low, all channels are off, and all internal registers
are reset to their default states. The device must be held in reset by an external source until all the power supplies
have stabilized. The IC contains an internal power on and undervoltage reset which becomes active when V5D,
V5A1, V5A2, or V5A3 fall below the undervoltage reset thresholds.
The ENABLE pin is an active high input pin which must be held high for normal operation of the device. When this
pin is held low all channels are either turned off or will remain in the last state, depending on how the enable
behavior of the channel is programmed via SPI Message #10. The default condition is that all channels are turned
off when the ENABLE pin is low.
The CLK pin is the main clock input for the device. The input thresholds are compatible with 3.3 V and 5.0 V logic
levels. No synchronization is required between the clock signal connected to the CLK pin and the SPI clock signal
(SCK). All internal clock signals of the TLE8242 (PWM signals, A/D sampling, diagnostics, etc.) are generated
from the this clock input. Also, this clock is required for the device to accept and respond to SPI messages.
1/f_clk
t₁₄
CLK
VIH_min
VIL_max
t₁₅
Figure 7 CLK Timing Diagram
The PHASE_SYNC pin is an input pin that can be used by the microcontroller to synchronize the PWM control
signals of multiple channels. The desired phase delay between the rising edge of the signal applied to the
PHASE_SYNC pin and the rising edge of the PWM signal of each channel can be programmed independently via
SPI message #6. The equation for calculating the offset is:
T_offset
=
PhaseSynchOffset
32 * F_PWM
Each time a pulse is received on the PHASE_SYNC pin, the IC will latch a bit which is reported via the response
to SPI message #19. (See SPI interface section for bit/message location.) This latch is cleared when the message
is read.
Note: The PWM periods are restarted when a rising edge is detected on the PHASE_SYNC pin. A periodic pulse
train on this pin will disturb the current regulation.
Note: After exiting the reset state, a pulse is needed on the PHASE_SYNC pin in order to synchronize the PWM
periods of the channels
Data Sheet
18
Rev. 1.0, 2010-02-09