Coherent light generators – Particular component circuitry – For driving or controlling laser
Reexamination Certificate
2002-12-27
2004-02-24
Scott, Jr., Leon (Department: 2828)
Coherent light generators
Particular component circuitry
For driving or controlling laser
C369S059110
Reexamination Certificate
active
06697401
ABSTRACT:
BACKGROUND OF THE INVENTION
Field of the Invention
The present application relates to a laser driver and a digital controller of a laser driver.
It is known how to trim a laser by soldering in resistors. This course of action is obviously difficult. Generally, the trimming and controlling of lasers by way of conventional laser drivers is not satisfactory.
SUMMARY OF THE INVENTION
It is accordingly an object of the invention to provide a laser driver and a digital laser driver control, which overcomes the above-mentioned disadvantages of the heretofore-known devices and methods of this general type and which make it possible to better control a laser. Specifically, a control system should be created which makes possible a user-friendly laser trimming.
With the foregoing and other objects in view there is provided, in accordance with the invention, a digital controller for a laser driver, comprising:
a register for storing control data serving to control an analog circuit of a laser driver;
a first interface for receiving operating data from a local memory and transmitting operating data to the local memory;
a second interface for receiving external user data; and
a control unit connected between and controlling a communication of data between the first interface, the second interface, and the register.
In other words, a digital control of a laser driver is implemented, in accordance with the invention, with the following elements: a register for storing control data which serve for controlling an analog circuit of the laser driver; a first interface for receiving operating data from a local memory; a second interface for receiving external user data; and a control unit for controlling data communication between the first and second interfaces and the register.
The control unit is advantageously constructed for generating the control data with the aid of the received operating and/or user data, and storing the control data in the register.
In accordance with an added feature of the invention, the control unit is configured to transmit operating data received via the first interface into the register at predetermined events and/or a predetermined time.
In accordance with an additional feature of the invention, the control unit is configured to retrieve the operating data from the local memory via the first interface and to store the retrieved operating data in the register.
In accordance with another feature of the invention, the control unit is configured to retrieve and store operating data in response to a switching on of the digital controller and/or in response to a resetting of the digital controller.
In accordance with a further feature of the invention, a logic circuit is provided for comparing a parity byte contained in the operating or user data with a parity byte generated by the control unit, and wherein the control data are generated and stored in dependence on a result of a comparison in the logic circuit. In one implementation, the control unit causes a shut-down of the laser driver in case of non-matching parity bytes.
In a preferred embodiment, the logic circuit is integrated in the register.
That is, the digital control is provided in a laser driver for controlling a laser, with: such a system includes a local memory, which is connected to the first interface; and an analog circuit which is connected to an output of the register and which serves for controlling a laser according to the control data stored in the register.
The digital control can take over the trimming operation and other communication and control functions of the laser driver. The information needed for this is contained in the operating and/or user data.
The operating data are preferably prestored (and unmodifiable by the user) in the local memory (for instance by the manufacturer). In order to allow an influencing control or status interrogation by the user in spite of this, the second interface is provided. But the control unit which controls the communication between the interfaces and the register allows only conditional user access to the local memory.
There is therefore provided, in accordance with the invention, a laser driver for controlling a laser, comprising:
a digital controller as outlined above;
a local memory connected to the first interface; and an analog circuit connected to an output of the register for controlling a laser in accordance with the control data stored in the register.
In accordance with again an added feature of the invention, the control data contain information about trimming the laser, and the analog circuit is configured for trimming the laser according to the information.
In accordance with a concomitant feature of the invention, the control unit includes an interface for receiving a signal containing information about which of the data stored in one of the local memory and the register may be overwritten, and wherein the control unit is configured for overwrite only the data in one of the local memory and the register that may be overwritten according to the information contained in the signal.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a laser driver and digital control of a laser driver, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
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Greenberg Laurence A.
Infineon - Technologies AG
Jr. Leon Scott
Locher Ralph E.
Stemer Werner H.
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