Automotive electrical network voltage regulation monitoring circuit

• US 4,374,380 A
• Filed: 12/04/1979
• Issued: 02/15/1983
• Est. Priority Date: 01/27/1979
• Status: Expired due to Term

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Meyer, Friedhelm, Giepen, Ulrich
• Primary Examiner(s): Waring, Alvin H.
• Application Number:
  US06/100,209
• Time in Patent Office: 1,169 Days
• Field of Search: 340/52 R, 340/52 F, 340/635, 340/645, 340/650, 340/653, 340/660, 322/99
• US Class Current: 340/660
• CPC Class Codes: G01R 31/006 on road vehicles, e.g. automobiles or trucks testing of ignition installations peculiar to internal combustion engines F02P17/00
• CPC Class Codes: H02J 7/00308 Overvoltage protection
• CPC Class Codes: H02J 7/0047 with monitoring or indicating devices or circuits
• CPC Class Codes: H02J 7/16 Regulation of the charging current or voltage by variation of field

Abstract

To provide a visible output indication, for example by an indicator light on a controller supervisory panel of the vehicle, of proper functioning of the voltage regulator power transistor, monitoring circuits are provided which sense the electrical condition of current flow through or the voltage condition of the field winding or output bus respectively by including a light emitting diode (LED) in an indicator circuit, for example by connecting it in series to the coupling resistor. In one form, a Zener diode Z (FIG. 1) is connected across the output bus with the LED in series, so that the LED will light if the output bus reaches a voltage which might damage the battery, for example due to short circuit or alloying-through of the output transistor T of the voltage regulator; in another form, an LED which preferably is green, LDg (FIG. 2), is connected across the output transistor, the green LED lighting if the output transistor functions properly, but extinguishing if the output transistor alloys-through; the LED with the Zener diode and the green LED can be provided together to form alternate outputs--green indicating proper operation and red already danger; in another form, an LED, preferably also green (FIG. 3) is connected across the field winding so that, if the output transistor T'"'"' should burn through, extinction of the green diode will indicate that the field no longer receives energization. Of course, the usually provided charge control lamp will then also light since the alternator will no longer furnish output, so that the combination of the green LED across the field with the charge control lamp again provides an alternate output indication, the extinction of the particular green LED pinpointing the trouble which caused the charge control lamp to light.

Claims

1. In an automotive-type self-contained on-board vehicular electrical network having a storage battery (13);

a generator (10) having a field winding (W) and supplying d-c output at a terminal (B+) for supply of power to a load bus (14) to charge the storage battery connected to the terminal (B+);

and a voltage regulator (12) having a power semiconductor (T, T'"'"') connected to the output (D+) of the generator and controlling power flow to the field winding (W) and having means (15) responsive to the voltage level on the power bus of the system controlling conduction of said power semiconductor in cycles to maintain an average predetermined current flow through the field winding in accordance with power requirements placed on the load bus,

and comprising,

a monitoring circuit to supervise proper operation of the voltage regulator power semiconductor (T, T'"'"') comprising

means sensing the electrical condition of the field winding (W) and including a light-emitting diode (LED), (LDr, LDg, LDg1) which, upon change of its illumination state, provides an output indication of the relation of the field winding with respect to the voltage thereacross, or with respect to a reference level;

wherein (FIG.

     1) the electrical condition is the voltage across the load bus (14) and the sensing means comprises

a Zener diode (Z) in series with said LED (LDr) connected across the load bus, said Zener diode breaking down and thus causing the LED to light when the voltage on the bus (14) exceeds a predetermined level due to short circuit of the voltage regulator semiconductor (T) and hence uncontrolled current flow through the field winding (W).

4. Monitoring circuit according to claim 1, further including an additional sensing means and an additional LED, said additional sensing means and LED comprising a circuit element (Rv1) and said additional LED, connected across the main power path of the voltage regulator power semiconductor (T), the voltage drop across said main power semiconductor providing operating voltage to said LED under normal operating conditions and then maintaining said additional LED in illuminated state, said additional LED extinguishing upon alloying-through or short circuit of said power semiconductor, resulting in uncontrolled current flow through the field winding (W) which, when continued, will cause the voltage across said load bus (14) to rise and change of the LED connected to the Zener diode to change to illuminated state to provide alternate "good" and "faulty" operating indication.

2. In an automotive-type self-contained on-board vehicular electrical network having a storage battery (13);

a generator (10) having a field winding (W) and supplying d-c output at a terminal (B+) for supply of power to a load bus (14) to charge the storage battery connected to the terminal (B+);

and a voltage regulator (12) having a power semiconductor (T, T'"'"') connected to the output (D+) of the generator and controlling power flow to the field winding (W) and having means (15) responsive to the voltage level on the power bus of the system controlling conduction of said power semiconductor in cycles to maintain an average predetermined current flow through the field winding in accordance with power requirements placed on the load bus,

and comprising,

a monitoring circuit to supervise proper operation of the voltage regulator power semiconductor (T, T'"'"') comprising

means sensing the electrical condition of the field winding (W) and including a light-emitting diode (LED) (LDr, LDg, LDg1) which, upon change of its illumination state, provides an output indication of the relation of the field winding with respect to the voltage thereacross, or with respect to a reference level, the electrical condition is current flow through the field winding (W) and the sensing means comprises a circuit element (Rv1) connecting the LED (LDg) in shunt across the power current path of the voltage regulator power semiconductor (T), the voltage drop across the power semiconductor (T) normally providing operating voltage to said LED to cause said LED to light when the power semiconductor is operating normally, said voltage being insufficient to maintain the LED in illuminated state upon alloying-through or short circuit of the power semiconductor and hence uncontrolled current flow through the field winding (W).

3. In an automotive-type self-contained on-board vehicular electrical network having a storage battery (13);

a generator (10) having a field winding (W) and supplying d-c output at a terminal (B+) for supply of power to a load bus (14) to charge the storage battery connected to the terminal (B+);

and a voltage regulator (12) having a power semiconductor (T, T'"'"') connected to the output (D+) of the generator and controlling power flow to the field winding (W) and having means (15) responsive to the voltage level on the power bus of the system controlling conduction of said power semiconductor in cycles to maintain an average predetermined current flow through the field winding in accordance with power requirements placed on the load bus,

and comprising,

a monitoring circuit to supervise proper operation of the voltage regulator power semiconductor (T, T'"'"') comprising

means sensing the electrical condition of the field winding (W) and including a light-emitting diode (LED) (LDr, LDg, LDg1) which, upon change of its illumination state, provides an output indication of the relation of the field winding with respect to the voltage thereacross, or with respect to a reference level

wherein (FIG. the electrical condition is voltage across the field winding (W), and the sensing means comprises a circuit element (Rv2) connecting the LED across the field winding, said LED being in illuminated state under normal operating conditions due to the voltage drop across the field winding, and indicating, by changing to extinguished state burn-out or open circuit condition of the power semiconductor (T'"'"'), thus interrupting a closed circuit to the field winding and isolating the field winding from current flow therethrough.