Datasheet

STPM01 Theory of operation
Doc ID 10853 Rev 8 23/60
capacitor should be connected between V
CC
and V
SS
, V
DDA
and V
SS
, V
DDD
and V
SS
. All
these capacitors must be located very close to the device.
The STPM01 contains a power on reset (POR) detection circuit. If the V
CC
supply is less
than 2.5 V then the STPM01 goes into an inactive state, all the functions are blocked
asserting a reset condition. This is useful to ensure correct device operation at power-up
and during power-down. The power supply monitor has built-in hysteresis and filtering,
which give a high degree of immunity to false triggering due to noisy supplies.
A bandgap voltage reference (VBG) of 1.23 V ±1 % is used as reference voltage level
source for the two linear regulators and for the A/D converters. Also, this module produces
several bias currents and voltages for all other analog modules and for the OTP module. The
bandgap voltage can be compensated regardless to the temperature variations with the
BGTC bits.
8.8 Load monitoring
The STPM01 includes a no load condition detection circuit with adjustable threshold. This
circuit monitors the voltage and the current channels and, when the measured voltage is
below the set threshold, the internal signal BIL becomes high. The information about this
signal is also available in the status bit BIL.
The no load condition occurs when the product between V
RMS
and I
RMS
register values is
below a given value. This value can be set with the LTCH configuration bits.
Four different no-load threshold values can be chosen according to the two configuration
bits LTCH (see Ta bl e 1 1 ).
Figure 17. Bandgap temperature variation
Table 11. No load detection thresholds
LTCH K
LTCH
0800
1 1600
2 3200
3 6400