CN105978077A - Step-by-step charger for vehicle-mounted communication equipment - Google Patents

Abstract

The step-by-step charger for in-vehicle communication equipment includes a charging power source, a charged power source and a reference voltage, and also includes a primary charging module and a secondary charging module; the primary charging module includes a first operational amplifier and a first charging device; The secondary charging module includes a second operational amplifier and a second charging device; the output terminals of the first charging device and the second charging device are respectively connected to a first capacitor and a second capacitor whose other end is grounded; and also includes a voltage divider circuit , the voltage divider circuit outputs the reference voltage, and its voltage value is between the voltage values of the charging power source and the charged power source. The invention reduces the ripple noise when the power supply is charged, can increase the data loading density, and improves the communication data transmission efficiency.

Description

In-vehicle communication equipment step-by-step charger

technical field

The invention belongs to the field of electronic communication, and relates to a communication charging device, in particular to a step-by-step charger for a vehicle communication device.

Background technique

In various electronic devices, different modules usually require different DC power sources, and usually one DC power source charges other power sources to obtain DC power sources with different potentials. For communication equipment, with the reduction of power consumption and signal voltage amplitude, the noise signal tolerance of the system is getting smaller and smaller, especially when power supply noise is superimposed on the signal, the impact on signal distortion is reflected with the reduction of power supply voltage an increasingly pronounced impact. In vehicle-mounted communication equipment, since the power supply itself is converted from mechanical energy, the power supply itself has strong ripples. In communication with high communication frequency and high information density, the impact of noise is even worse.

Contents of the invention

In order to reduce the signal distortion caused by power supply noise being superimposed on the communication signal, the invention discloses a step-by-step charger for vehicle communication equipment.

The vehicle-mounted communication equipment step-by-step charger of the present invention, the vehicle-mounted communication equipment step-by-step charger, includes a charging power supply, a charged power supply and a reference voltage, and also includes a primary charging module and a secondary charging module;

The primary charging module includes a first operational amplifier and a first charging device, the output terminal of the first operational amplifier is connected to the control terminal of the first charging device, the input terminal of the first charging device is connected to the charging power supply, and the output terminal is connected to the charging device. The inverting input terminal of the first operational amplifier, the positive input terminal of the first operational amplifier is connected to the reference voltage, and also includes a current limiting resistor connected between the output terminal of the first charging device and the ground;

The secondary charging module includes a second operational amplifier and a second charging device, the output terminal of the second operational amplifier is connected to the control terminal of the second charging device, the input terminal of the second charging device and the positive electrode of the second operational amplifier The output end of the first charging device is connected to the input end; the output end of the second charging device is connected to the reverse input end of the second operational amplifier and the charged power supply;

The output ends of the first charging device and the second charging device are respectively connected to a first capacitor and a second capacitor whose other end is grounded;

A voltage dividing circuit is also included, the voltage dividing circuit outputs the reference voltage, and its voltage value is between the voltage values of the charging power source and the charged power source.

Preferably, the voltage dividing circuit is a resistor string, the two ends of the resistor string are respectively connected to the charging power source and the charged power source, and any internal node of the resistor string is output as a reference voltage.

Preferably, the first charging device and/or the second charging device are NMOS transistors.

Preferably, the step-by-step charger for the on-vehicle communication device also includes a pre-charging circuit, the function of the pre-charging circuit is: before the first and second operational amplifiers work, the output terminal of the first charging device is pre-charged to the pre-charged Charging voltage, the pre-charging voltage is between the reference voltage and the charged voltage value, after the pre-charging is completed, the pre-charging circuit is closed before the first and second operational amplifiers work.

Further, the voltage divider circuit also includes a precharge voltage output terminal, the precharge voltage value output by the precharge voltage output terminal is between the reference voltage and the voltage value of the charged power supply; the precharge circuit is composed of a third Composed of an operational amplifier, a timer and a switching device, the positive input terminal of the third operational amplifier is connected to the output terminal of the precharge voltage, the reverse input terminal is connected to the output terminal of the third operational amplifier and the input terminal of the switching device, and the output terminal of the switching device The terminal is connected to the output terminal of the first charging device, and the control terminal of the switching device is connected to a timer, and the timer turns on the switching device after power-on, and turns off the switching device after a preset period of time.

The step-by-step charger for vehicle-mounted communication equipment described in the present invention is applied in the DC charging process, and one charge is divided into two charging processes, which reduces the ripple noise during power supply charging, and at the same time, the intermediate voltage gradually follows the charged voltage. As the charging voltage rises, the amplitude of the charging voltage difference decreases linearly, and the voltage change process is stable without sudden changes, which further reduces system noise and secondary interference to data information. Due to the reduction of power supply ripple, the data loading density can be increased, and the communication data can also be improved. transmission efficiency.

Description of drawings

Fig. 1 is a schematic diagram of a specific implementation and application mode of a step-by-step charger for a vehicle-mounted communication device according to the present invention;

Fig. 2 is a schematic diagram of a specific embodiment of the voltage divider circuit of the present invention;

The names of reference signs in the figure are: VH-charging power supply, VL-charged power supply, VP-precharge voltage, VM-intermediate voltage, VREF-reference voltage, AMP1-first operational amplifier, AMP2-second operational amplifier, AMP3 -Third operational amplifier, M1-first charging device, M2-second charging device, R1-current limiting resistor, RL-load, R2-first voltage dividing resistor, R3-second voltage dividing resistor, R4-third Divider resistance, C1-first capacitor, C2-second capacitor, K-switching device.

detailed description

The specific embodiment of the present invention will be further described in detail below in conjunction with the accompanying drawings.

A step-by-step charger for vehicle-mounted communication equipment according to the present invention includes a charging power source, a charged power source and a reference voltage, and also includes a primary charging module and a secondary charging module;

The primary charging module includes a first operational amplifier and a first charging device, the output terminal of the first operational amplifier is connected to the control terminal of the first charging device, the input terminal of the first charging device is connected to the charging power supply, and the output terminal is connected to the charging device. The inverting input terminal of the first operational amplifier, the positive input terminal of the first operational amplifier is connected to the reference voltage, and also includes a current limiting resistor connected between the output terminal of the first charging device and the ground;

The secondary charging module includes a second operational amplifier and a second charging device, the output terminal of the second operational amplifier is connected to the control terminal of the second charging device, the input terminal of the second charging device and the positive electrode of the second operational amplifier The output end of the first charging device is connected to the input end; the output end of the second charging device is connected to the reverse input end of the second operational amplifier and the charged power supply;

The output ends of the first charging device and the second charging device are respectively connected to a first capacitor and a second capacitor whose other end is grounded;

A voltage dividing circuit is also included, the voltage dividing circuit outputs the reference voltage, and its voltage value is between the voltage values of the charging power source and the charged power source.

As shown in FIG. 1 , assuming that the charging voltage VH=10, the initial value of the charged voltage VL is zero, and VREF is preset as (VH+VL)/2. In the initial state VREF=5V, the connection form of the first operational amplifier AMP1 makes its output terminal voltage close to the positive input terminal voltage VREF, that is, the intermediate voltage VM at the output terminal of the first operational amplifier passes through a circuit centered on the first operational amplifier. After the stage charging module, the obtained intermediate voltage VM=5V.

The first capacitor C1 at the output end of the primary charging module in FIG. 1 and the current limiting resistor R1 together form an output filter to reduce output ripple. At the same time, the current limiting resistor R1 can also limit the maximum current of the first charging device M1 to avoid device damage, and the first capacitor C1 is used as an energy storage capacitor for the intermediate voltage VM.

The secondary charging module uses the intermediate voltage VM as the power supply to charge the second capacitor C2. The second operational amplifier AMP2 is connected in the same way as the first operational amplifier AMP1. The second operational amplifier uses the load resistor RL as the primary charging module. The role of current limiting resistor R1.

The charging devices in the two charging modules preferably use NMOS devices with stronger current capability in the same area.

The secondary charging module makes the voltage value of the charged voltage VL approach to the voltage value of VM.

The voltage divider circuit is used to generate the reference voltage VREF, the key is to make its voltage value between the charging voltage VH and the charged voltage VL at all times, so that VREF can rise with the rise of VL and fall with the fall of VH.

Figure 2 shows a common way of a voltage divider circuit, which is formed by connecting voltage divider resistors in series. By setting the ratio of the resistance values at both ends of the VREF marked node in Figure 2, different functional relationships between VREF and VH and VL can be obtained. For example, for a typical situation where the first voltage dividing resistor R2 is equal to the sum of the second voltage dividing resistor R3 and the third voltage dividing resistor R4, VREF=(VH+VL)/2.

The following describes the charging process of the present invention,

For the initial state of VH=10V, VL=0V, VREF=VM=5V at this time, but when VL is charged to 1V, VREF= (10+1)/2=5.5V at this time, VM at this time is in a The steady-state voltage in the stage charging module is 5.5V, and for the state of the charged voltage VL=1V, the voltage difference is still maintained at about 4.5V.

When VL is charged to 2V, VREF= (10+2)/2= 6V, that is, VREF=6V, VM will be charged to 6V, at this time, for the charged voltage VL=2V, the voltage difference is maintained at about 4V.

When VL is charged to be closer to VH, such as 9V, then VREF=(10+9)/2=9.5V, VM will be charged to 9.5V. At this time, for the state of charged voltage VL=9V, the voltage difference Maintain around 0.5V.

It is not difficult to see from the above list of states that in the present invention, a two-stage charging mode is adopted. While completing the basic charging function to make VL continuously rise to approaching VH, at the first-stage charging module, the voltage between the intermediate voltage VM and the charging voltage VH difference; and at the secondary charging module, the voltage difference between the intermediate voltage VM and the charged voltage VL is limited to less than the range of VH-VL, thereby actually reducing the traditional primary charging mode, due to the excessive voltage difference The phenomenon that the power supply outputs a large current and easily forms a large ripple. At the same time, the two-stage charging form is used, so that the output stage device can choose a low-voltage device with a lower withstand voltage value, reducing the withstand voltage process of the entire integrated circuit chip, thereby avoiding the use of expensive high-voltage chip manufacturing processes, and completing high-voltage charging with a relatively cheap low-voltage process. process, saving manufacturing costs.

The intermediate voltage gradually increases with the charged voltage, the charging voltage difference decreases linearly, and the voltage change process is stable without sudden changes, which further reduces system noise and secondary interference to data information. Due to the reduction of power supply ripple, data loading can be improved. Density, also improves communication data transmission efficiency.

In the specific embodiment shown in Fig. 1, a preferred embodiment of the present invention has been provided, the step-by-step charger of the vehicle communication equipment also includes a pre-charging circuit, and the function of the pre-charging circuit is: in the first and Before the second operational amplifier works, the output terminal of the first charging device is precharged to a precharge voltage, and the precharge voltage is between the reference voltage and the charged voltage value. After the precharge is completed, the precharge circuit is The first and second operational amplifiers are turned off before operation.

A specific implementation of the pre-charging circuit is shown in Fig. 1, and the voltage divider circuit also includes a pre-charging voltage output terminal, and the pre-charging voltage value output by the pre-charging voltage output terminal is between the reference voltage and the voltage of the charged power supply. between values; the precharge circuit is made up of a third operational amplifier AMP3, a timer and a switching device, the forward input of the third operational amplifier is connected to the precharge voltage output, and the reverse input is connected to the third operational amplifier The output end and the input end of the switch device K, the output end of the switch device is connected to the output end of the first charging device, the control end of the switch device is connected to a timer, and the timer turns on the switch device K after power-on, and The switching device is turned off after a preset period of time.

After the timer is powered on, the switching device is turned on, and the voltage divider circuit generates a precharge voltage at the same time. The third operational amplifier charges the output terminal according to the precharge voltage value. Although the connection method of the third operational amplifier makes the output of the third operational amplifier The steady-state voltage of terminal pre-charging is the pre-charging voltage value, but in the present invention, it is not necessary to make the third operational amplifier continue to work until it is charged to the pre-charging voltage value, as long as the charging process of the preset time period makes the VM terminal It only needs to increase the voltage to the vicinity of the pre-charge voltage value, and of course the pre-charge voltage value can also be charged.

The pre-charging circuit setting is used to pre-charge the voltage of the VM terminal to a certain level, which reduces the absolute pressure difference when charging the VM terminal from the charging voltage VH, thereby reducing the ripple. At the same time, for the first-level charging module, the power device The maximum voltage difference during continuous operation is the difference between the charging voltage VH and the pre-charged voltage. The pre-charging behavior actually reduces the difference, so that the power device part of the primary charging module can all use a lower voltage The advanced integrated circuit manufacturing process reduces the cost of chip manufacturing. The switch device can be MOS, triode or transmission gate, etc.

The foregoing are various preferred embodiments of the present invention. If the preferred implementations in each preferred embodiment are not obviously self-contradictory or based on a certain preferred implementation, each preferred implementation can be used in any superposition and combination. The above examples and the specific parameters in the examples are only for clearly expressing the inventor's invention verification process, and are not used to limit the scope of patent protection of the present invention. The scope of patent protection of the present invention is still subject to its claims. The equivalent structural changes made in the specification and drawings of the present invention should be included in the protection scope of the present invention in the same way.

Claims (5)

1. vehicular communication equipment multiple step format charger, including charge power supply, is electrically charged power supply and reference voltage, it is characterised in that also include one-level charging module and two grades of charging modules；

Described one-level charging module includes the first operational amplifier, the first charging device, the outfan of described first operational amplifier connects the first charging device and controls end, the input of described first charging device connects charge power supply, outfan connects the reverse input end of the first operational amplifier, the positive input of described first operational amplifier connects reference voltage, also includes the current-limiting resistance being connected between the first charging device outfan and ground；

Described two grades of charging modules include the second operational amplifier, the second charging device, the outfan of described second operational amplifier connects the second charging device and controls end, and the input of described second charging device and the positive input of the second operational amplifier connect the outfan of the first charging device；Outfan and the reverse input end of the second operational amplifier of the second charging device and be electrically charged power supply and connect；

The outfan of described first charging device and the second charging device is connected to the first electric capacity and second electric capacity of other end ground connection；

Also including bleeder circuit, described bleeder circuit exports described reference voltage, and makes its magnitude of voltage between charge power supply and the magnitude of voltage being electrically charged power supply.

2. vehicular communication equipment multiple step format charger as claimed in claim 1, it is characterised in that described bleeder circuit is resistance string, and resistance string two ends connect charge power supply respectively and are electrically charged power supply, and the inside arbitrary node of resistance string exports as reference voltage.

3. vehicular communication equipment multiple step format charger as claimed in claim 1, it is characterised in that described first charging device and/or the second charging device are NMOS tube.

4. vehicular communication equipment multiple step format charger as claimed in claim 1, it is characterized in that, described vehicular communication equipment multiple step format charger also includes pre-charge circuit, the function of described pre-charge circuit is: before first and second operational amplifier works, first charging device outfan is precharged to pre-charge pressure, described pre-charge pressure is between reference voltage and to be electrically charged between magnitude of voltage, and after preliminary filling completes, described pre-charge circuit is closed before first and second operational amplifier works.

5. vehicular communication equipment multiple step format charger as claimed in claim 4, it is characterised in that described bleeder circuit also includes pre-charge pressure outfan, and the precharging voltage value of described pre-charge pressure outfan output is between reference voltage and the magnitude of voltage being electrically charged power supply；Described pre-charge circuit is made up of the 3rd operational amplifier, timer and switching device, the positive input of described 3rd operational amplifier connects pre-charge pressure outfan, reverse input end connects the 3rd operational amplifier output terminal and switching device input, described switching device outfan connects the outfan of the first charging device, the control end of described switching device is connected with timer, described timer opens switching device, and closing switch device after preset time period after the power-up.