JPS62247403A - Electronic controller - Google Patents

Abstract

PURPOSE:To minimize the power loss of a control element and to attain the direct control even with a heavy load by programming the port of the control element into an application for input when the control element is controlled at a high level. CONSTITUTION:When a transistor TR4 is controlled at a high level, an output buffer 2a is set at a high impedance by an input/output switching signal and a port is programmed into an application for input. As a result, no current flows from the buffer 2a. Furthermore no current flows to an input buffer 2b since this buffer is also set at a high impedance. Therefore no current flows virtually from an element 1. Thus the current flowing to the TR4 is decided only by a resistance 7 connected to a power supply. While the port of the element 1 is programmed into an application for output in case the TR4 is controlled at a low level.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electronic control device for controlling solenoids, various actuators, etc. used in vehicles.

[Conventional technology]

FIG. 2 is an equivalent circuit diagram showing the configuration of a conventional electronic control device. In the figure, numeral 1 denotes an element whose port having an output buffer 2 and an input buffer 'not shown can be programmed for input or output, and numeral 3 denotes its internal bus. A transistor 4 is a control element controlled by this element 1, and its pace is connected to the element 1 via a current limiting resistor 5, and its collector is a solenoid 6f which is a load.
, and the emitter is grounded. Further, 7 is a pull-up resistor whose one end is connected to the power supply and the other end is connected between the element 1 and the resistor 5. Here, a solenoid is taken as an example of a load, but there are other loads such as engine injectors, various actuators, electromagnetic valves, etc.

In the nine control device configured in this way, when transistor 4 is controlled by wire 1, the port is programmed to be fixed for output, and when transistor 4 is controlled at high level, the output is high, and when controlled at low level. was outputting low.

By the way, the general output level voltage of the element 1 is, for example, when the power supply voltage is 5V, the low level voltage is 1.6.
Although this is a small value of about 0.5 V when a load current of mA is absorbed, the high level voltage becomes a low voltage value of about 2.5 V even when a load current of 100 to 200 μA is drawn. Therefore, if the load current at high level is required to exceed the above value, connect a resistor 7 between the power supply and the output as shown in the figure, and use this current IR to compensate for the shortfall in the output current l0)i of element 1. was.

[Problem that the invention seeks to solve]

Conventional electronic control units are configured as described above, but
The current IOH flows through element 1, and l0HX inside element 1.
A power loss of (power supply voltage - high level voltage VCII) occurs. Therefore, when the load is heavy, the element generates a large amount of heat, and it becomes impossible to control the load above a certain level.

Moreover, when controlling a control element with a heavy load, there is a problem in that it is even necessary to add a cable e-N having a high input impedance to the front of the control element.

This invention is a ninth step in solving the above-mentioned problems, and aims to provide an electronic control device in which the power loss of the elements can be minimized and which can directly control η1 even under heavy loads.

[Ninth let go to solve all problems]

In the electronic control device according to the present invention, when controlling a control element at a high level, the port of the element is programmed for input, and when controlling the control element at a low level, the port of the element is programmed for output.

[For production]

In this invention, when controlling a control element at a high level, the output buffer of the element is set to high impedance and the port is programmed for input, so almost no current flows from the element, and the current flowing to the load is connected to the power supply. determined only by the resistance applied.

〔Example〕

FIG. 1 is a circuit diagram showing the configuration of an electronic control device according to an embodiment of the present invention. In the figure, 2a is an output buffer, 2b
2 is an input buffer, and the other configurations are the same as those of the conventional device shown in FIG. 2, so corresponding parts are given the same reference numerals and their explanation will be omitted.

In the electronic control device having such a configuration, when controlling the transistor 4 at a high level, the output buffer 2a'1 is set to high impedance by the input/output switching signal, and the port is programmed as an input button. By doing this, the fcc current does not flow from the output buffer 2a, and since the human capacitor 2b also has high impedance, /F! The L current does not flow, and almost no current flows from element 1. Therefore transistor 4
The current flowing to is determined only by the t resistor 7 connected to the power supply.

Note that when the transistor 4t is controlled at a low level, the port of the element 1 is programmed for output as in the conventional case.

〔Effect of the invention〕

As described above, according to the present invention, when the control element is controlled at a high level, the port of the element is programmed for input, so the element rC can be controlled without passing current, and therefore the element power loss can be minimized, making it possible to directly control even heavy loads that could not be directly controlled in the past. Moreover, in the conventional device, I/,
! This has advantages such as eliminating the need for a tight resistor that limits the current flowing out from the electrons.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of an electronic control device according to an embodiment of the present invention, and FIG. 2 is a circuit diagram of a conventional electronic control device. DESCRIPTION OF SYMBOLS 1... Element, 2a... Output buffer, 2b... Input buffer, 4... Control element (transistor), 6...
...Solenoid, 7...Resistance. Note that the same reference numerals 4 and 4 in the drawings indicate corresponding parts.

Claims (1)

[Claims] Equipped with a port with input buffer and output buffer,
Consisting of an element that can program this port for input or output, a control element controlled by this element, and a resistor connected to a power source that biases the element between this control element and the element. An electronic control device for controlling a load, characterized in that a port of the control element is programmed for input when the control element is controlled at a high level, and for output when the control element is controlled at a low level. .