TLE5012B
Interfaces
User’s Manual
47
Rev. 1.2, 2018-02
The PWM frequency is derived from the digital clock via
(5.7)
The min/max values given in
take into account the internal digital clock variation specified in
TLE5012B
Data Sheet
. If external clock is used, the variation of the PWM frequency can be derived from the variation of the
external clock using
.
Pulse length convertion to angle value
The length of the duty cycle represents the angle value. Whatever the absolute angle value is, the t
on
time depends
on the angle value calculated by the TLE5012B with resolution up to 0.100°. The 0.100° resolution is due to the
fact that with 12bit resolution (4096 steps) 100% of the duty cycle can be mapped, but only 87.5% of the duty cycle
translates to angle values. This means that the 360° degees must be mapped with only 3584 steps (87.5%*4096),
so effective resolution is 0.100°.
The angle value can be measured with the following formula, where t
ON
is the length of the pulse in seconds and
f
PWM
is the frequency selected:
(5.8)
The frequency for the PWM interface can be selected via the register MOD_4 (IFAB_RES bits) as described in
for the PWM derivates with the default frequencies.
A t
ON
of more than 93.75% duty cycle would indicate an error as described in
.
Table 5-7
PWM interface
Parameter
Symbol
Values
Unit
Note / Test Condition
Min.
Typ.
Max.
PWM output frequencies
(Selectable by IFAB_RES)
f
PWM1
232
244
262 Hz
1)
1) Not subject to production test - verified by design/characterization
f
PWM2
464
488
525 Hz
f
PWM3
929
977
1050 Hz
f
PWM4
1855
1953
2099 Hz
Output duty cycle range
DY
PWM
6.25
93.75 %
Absolute angle
2
%
Electrical Error (S_RST;
S_VR)
1)2)
2) Both hardware and software resets will generate an Electrical Error duty cycle for the first PWM pulse after the reset
(S_RST). After readout, S_RST bit will be set to “0”, so the second PWM pulse will indicate an angle.
98
%
System error (S_FUSE;
S_OV; S_XYOL;
S_MAGOL; S_ADCT)
0
1 %
Short to GND
99
100 %
Short to V
DD
, power loss
4096
*
24
2
*
IFAB_RES
DIG
PWM
f
f
=
PWM
PWM
ON
f
f
t
Angle
1
*
%
5
.
87
360
*
1
*
%
25
.
6
]
[
°
⎟⎟
⎠
⎞
⎜⎜
⎝
⎛
−
=
°