L5953_07 STMICROELECTRONICS [STMicroelectronics], L5953_07 Datasheet - Page 14

• Manufacturer Part Number: L5953_07
• Description: Multiple switching voltage regulator
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

Functional description
2
2.1
2.2
2.3
2.4
2.5
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Functional description
REG1 stand-by regulator
The stand-by regulator
selectable by means of the ADJ pin:
- leaving the ADJ pin open, the output voltage is 5V;
- connecting the ADJ pin to the Vstby pin the output voltage becomes 3.3V.
This regulator is supplied by STCAP pin and provide the reset information.
It has a current protection which limits the maximum allowable output current.
Reset
The RES pin
the stand-by regulator is not in regulation (including thermal shutdown and faults). The
indication that REG1 is in regulation is delayed by a time set up by the external capacitor CT.
When the RES is switched on, HSD1, HSD2, REG2, PWM are turned off and until the RES
is forced to zero only the REG1 and low Voltage Warnings are active.
Low voltage warning
This circuit is able to sense two different voltages through external resistors to increase the
overall flexibility.
If S1 pin voltage is higher than Vst, the output of mos M1 is off: W1 is floating and can be
pulled up by an external resistor. If S1 pin voltage goes down and becomes lower than Vst,
the mos M1 is turned on and forces W1 to zero. The same thing happens for S2 - W2.
The outputs W1 and W2 can be connected together to get a single output.
REG2 linear voltage regulator
REG2 is a linear voltage regulator
voltage (between 1.5V and 3.3V) is fixed by an external divider. It can be turned on/off by
SPI. It has a current protection which limits the maximum allowable output current.
High side drivers
Two high-side driver
L5953. They are protected against short to ground: the short circuit protection limits the
maximum output current.
A diagnostic procedure is available to detect open load, short to battery and overcurrent.
Open load and short to battery can be reveal only in test mode while overcurrent is active
only during normal operation of the device. (see
(Figure
(Figure
(Figure
8.) is an open collector that is activated (that is forced to zero) when
(Figure
9.)
10.) with charge pump controlled by SPI are available inside
7.) output voltage can be 5V or 3.3V. It is externally
(Figure
7.) with a dedicated supply pin VIN. The output
4.2 on page
18)
L5953