L9911V STMICROELECTRONICS | Alldatasheet
Document overview
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- PDF pages: 19
Technical content
Datasheet sections
- 1 Circuit operation
- 1.1 Voltage regulation
- 1.2 Protection
- 1.3 Diagnosis
- 1.4 Load response control
- 2 Pin description
- 3 Electrical specification
- 3.1 Absolute maximum ratings
- 3.2 Thermal data
- 3.3 Electrical characteristics
- 3.4 Principle of phase regulation
- 4 Package information
- 5 Revision history
Features
■ Fully monolithic design ■ High side field driver ■ Thermal protection ■ Field short circuit protection ■ Protected diagnostic lamp driver ■ Protected high side relay driver ■ Complex diagnostics ■ Load response control ■ DFM output (field monitor)
Description
The L9911 is a monolithic multifunction alternator voltage regulator intended for use in automotive application. It includes the control section, the field power stage, fault diagnostic circuit which drives a warning lamp, and the protection against short circuits. '!0'03 Multiwatt8 Table 1. Device summary
1 Circuit operation
The alternator's voltage regulator performs the following main functions: 1. voltage regulation 2. protection 3. control fault diagnosis 4. load response control
1.1 Voltage regulation
The alternator voltage is compared with a reference voltage in an amplifier, whose output determines the switching frequency of output power MOS whose current excites the coil of the alternator; as the regulator is in fixed-frequency topology, the field switching frequency does not depend on the alternator characteristics. The regulators have an integrated filter in the voltage sensing path guaranteeing the correct behaviour of the devices also when the rectifier diodes feature very high switching spikes. The internal filtering allows the usage of the device also with very long cables connecting the alternator to the battery with an impedance so high to cause a superimposed ripple on the alternator voltage higher than 5- 6V. Consequently it doesn't need, in the standard application, any external component. Anyway an external capacitor (2.2µF) must be inserted between A+ and ground when using the device with very long cables.
1.2 Protection
It is present a protection against short circuits of the lamp and the relay power drivers (L) and of the field power driver (F+), a thermal drivers shutdown protection and an overvoltage protection of L power drivers.
1.3 Diagnosis
The circuit detects fault conditions related to the phase and F+ status and receives informations from one of the three alternator phases. In order to prevent spurious indications, fault warnings are not displayed immediately but are delayed by a fixed time.
1.4 Load response control
The internal circuit regulates the soft start characteristics (activated always at engine start) and the soft attack characteristics.
2 Pin description
Figure 1. Pin connection (top view) Table 2. Pin description 4 L Lamp terminal low side driver; relay terminal high side driver.
3 Electrical specification
3.1 Absolute maximum ratings
Tj = -40 to 150 °C, unless otherwise specified.
3.2 Thermal data
3.3 Electrical characteristics
Tj = -40 °C to 150 °C; unless otherwise specified. Table 3. Absolute maximum ratings Table 4. Thermal data Table 5. Electrical characteristics
Regulated voltage & thermal drift. Table 5. Electrical characteristics (continued)
customization for L9911 in the table below. Figure 2. V reg-1 Table 8. Correspondence of frequency (typical values) to application features Table 9. Customization of L9911: combination of LRC, regulation, and application options
6 Pole
8 Pole
3.4 Principle of phase regulation
voltage from falling below VPHH1. If phase peak voltage drops below VPHL1, phase regulation does not work. Figure 8. Application diagram Figure 9. High side/low side driver saturation Figure 10. Test mode to cancel soft-start/attack Figure 11. Soft-start enable frequency range
4 Package information
specifications, grade definitions and product status are available at: www.st.com. ECOPACK® is an ST trademark. Figure 16. Multiwatt8 mechanical data and package dimensions
5 Revision history
Table 11. Document revision history 22-Jun-2004 1 Initial release. Updated Figure 10, 11 and 14; Add Table 7. 07-Nov-2005 3 Updated Table 5. 28-Nov-2005 4 Added the L9911C part number. 11-Jul-2007 5 Document reformatted. Updated order codes, see Table 1: Device summary. LRC, regulation, and application options. regulation, and application options. 25-Jan-2011 8 Updated Table 5: Electrical characteristics. and application options on page 11. regulation, and application options on page 11. 19-Sep-2013 12 Updated Disclaimer.