CN205356145U - Difference PWM modulator and because electric current mould DCDC converter of this modulator - Google Patents

Abstract

Difference PWM modulator and because electric current mould DCDC converter of this modulator is not suitable for the piece problem of resistance detection output current's electric current mould DCDC converter outward of utilizing in order to solve traditional single -ended modulator. The utility model discloses a difference PWM modulator includes: single -ended control voltage amplifies through gain stage A1 with common mode voltage's differential mode voltage, and feedback current's differential voltage amplifies through gain stage A2, and the input comparator after gain stage A1 and gain stage A2 amplify carries out the comparison, produces the PWM modulation and exports, and the first feedback voltage CS and the 2nd feedback voltage VOUT's difference is feedback current's differential voltage. The utility model discloses because the detection resistance RS of the electric current mould DCDC converter of this modulator sets up in exporting the route, utilize the differential voltage on the resistance RS to realize peak value or the modulation of valley point current mould PWM. The utility model discloses a difference PWM modulator is applicable to the application that battery charger etc. Needs resistance detection output current outside the piece.

Description

Differential PWM modulation device and the DC/DC transducer based on this manipulator

Technical field

This utility model relates to a kind of PWM modulator and the DC/DC transducer based on this manipulator.

Background technology

The DC-DC converter that PWM controller chip is constituted in conjunction with discrete switch mosfet, has that current capacity is strong, high reliability.But owing to not having current feedback path, such DCDC many employings voltage-mode controls, namely only feeding back DCDC output voltage, such as Fig. 1, its shortcoming is that load regulation is worse than current-mode, and voltage-mode controls required more complicated compensation network.

Resistance R can also be added in lower pipe MN source_S, such as Fig. 2, introduce current feedback, thus realizing electric current restriction or current-mode controls.But it only have detected the electric current of a phase place in PWM cycle, it is impossible to the accurately size of reaction output electric current.

In the application such as battery charger, output voltage and cell voltage, then output electric current and charging current, in order to be precisely controlled charging current, it is necessary to adds detection resistance R in outgoing route_S, such as Fig. 3.In order to realize current-mode control, additionally add detection resistance in MN source if the same with Fig. 2, then can worsen conversion efficiency.

According to traditional single-ended manipulator, such as Fig. 4, that comparator CMP compares is single-ended control voltage V_CTRLWith ramp voltage V_RAMP, it is not particularly suited for the application of Fig. 3.

Utility model content

The purpose of this utility model is the problem not being suitable for utilizing the DC/DC transducer of off chip resistor detection output electric current in order to solve traditional single-ended manipulator, and this utility model provides a kind of differential PWM modulation device and the DC/DC transducer based on this manipulator.

Differential PWM modulation device of the present utility model, described manipulator includes:

Differential amplifier, for input reference voltage V_REFAnd feedback voltage V_OUT, it is thus achieved that single-ended control voltage V_CTRL；

Gain stage A1, for by single-ended control voltage V_CTRLWith common-mode voltage V_COMDifferential voltage V_CTRL–V_COMAmplify, it is thus achieved that differential signal V_A1；

Gain stage A2, for amplifying the differential voltage of feedback current, it is thus achieved that differential signal V_A2；

Comparator, for by differential signal V_A1With differential signal V_A2Produce PWM output more afterwards.

Described common-mode voltage V_COM, it is additionally operable to slope compensation.

Described common-mode voltage V_COMGeneration circuit include NMOS tube M_S1, NMOS tube M_S2, electric capacity C_COMWith current source Icom；

NMOS tube M_S1Source electrode and NMOS tube M_S2Drain electrode connect, NMOS tube M_S1Grid and drain electrode meet current source and electric capacity C simultaneously_COMOne end, electric capacity C_COMThe other end and NMOS tube M_S2Source electrode connect；NMOS tube M_S2Grid connect square-wave signal d；

NMOS tube M_S1Drain electrode and described electric capacity C_COMOne end between voltage be common-mode voltage V_COM。

Described gain stage A1 includes NMOS tube M_A1, NMOS tube M_A2, resistance R₁, resistance R₂With current source I_A1；

NMOS tube M_A1Grid input control voltage V_CTRL, NMOS tube M_A2Grid common mode input V_COM；

NMOS tube M_A1Source electrode and NMOS tube M_A2Source electrode meet current source I simultaneously_A1；

NMOS tube M_A1Drain electrode and resistance R₁One end connect, resistance R₁The other end and resistance R₂One end connect, resistance R₂The other end and NMOS tube M_A2Drain electrode connect；

NMOS tube M_A2Drain electrode output and NMOS tube M_A1Drain electrode output input compare to comparator.

Described gain stage A2 includes nmos pass transistor M_B1, nmos pass transistor M_B2With current source I_A2；

NMOS tube M_B1Grid input the first feedback voltage CS, NMOS tube M_B2Grid input the second feedback voltage V_OUT；Described first feedback voltage CS and described second feedback voltage V_OUTThe differential voltage that difference is feedback current；

NMOS tube M_B1Source electrode and NMOS tube M_B2Source electrode meet current source I simultaneously_A2；

NMOS tube M_B2Drain electrode output and NMOS tube M_B1Drain electrode output input compare to comparator.

Also provide for a kind of DC/DC transducer based on described differential PWM modulation device, the detection resistance R of described DC/DC transducer_SIt is arranged in outgoing route, utilizes resistance R_SOn differential voltage realize peak value or valley point current mould PWM, described resistance R_SOn differential voltage be the differential voltage of described feedback current.

Described DC/DC transducer includes differential PWM modulation device, logic controller, two buffers, not gate, NMOS tube MN, PMOS MP, inductance L, electrochemical capacitor C_OUTWith resistance R_S；

The output of differential PWM modulation device inputs to logic controller, described logic controller output square-wave signal d, described square-wave signal d inputs the grid to PMOS MP by the first buffer and through not gate, described square-wave signal d is by the grid of the second buffer input to NMOS tube MN, the drain electrode of the drain electrode of described PMOS MP and NMOS tube MN is connected with one end of inductance L simultaneously, the other end of described inductance L and resistance R_SOne end connect, described resistance R_SThe other end and electrochemical capacitor C_OUTPositive pole connect, described electrochemical capacitor C_OUTThe source electrode of negative pole and NMOS tube MN connect power supply ground simultaneously；The source electrode of described PMOS MP meets the positive pole V of power supply_IN。

The beneficial effects of the utility model are in that, differential PWM modulation device of the present utility model is applicable to battery charger etc. needs the application of off chip resistor detection output electric current, it is possible to namely this resistance of multiplexing made output electric current and controlled, and makes again current ripples and detects for PWM；Common-mode voltage V_COMGeneration circuit extremely simple, be simultaneously achieved common-mode voltage produce and slope compensation function.The existence of this utility model gain stage A1 and gain stage A2, it is simple to the independent gain adjusting each road input differential signal, thus regulating the overall gain of PWM modulator so that stability Design is more prone to.V_CTRL–V_COMDifference mode signal, as controlling voltage, considerably increases dynamic range, it is allowed to support broader current range under less running voltage.

Accompanying drawing explanation

Fig. 1 is the principle schematic of voltage-mode DC-DC converter；

Fig. 2 is the principle schematic of the DC/DC transducer adopting one-terminal current feedback；

Fig. 3 is the principle schematic of the DC/DC transducer described in detailed description of the invention；

Fig. 4 is the principle schematic of traditional single-ended manipulator；

Fig. 5 is the principle schematic of the differential PWM modulation device described in detailed description of the invention；

Fig. 6 be in Fig. 5 gain stage A1, gain stage A2 and comparator implement circuit；

Fig. 7 is common-mode voltage V in detailed description of the invention_COMGeneration circuit；

Fig. 8 is the oscillogram of square-wave signal d in detailed description of the invention；

Fig. 9 is common-mode voltage V in detailed description of the invention_COMOscillogram.

Detailed description of the invention

Present embodiment is specially a kind of DC/DC transducer, as it is shown on figure 3, include differential PWM modulation device, logic controller, two buffers, not gate, NMOS tube MN, PMOS MP, inductance L, electrochemical capacitor C_OUTWith resistance R_S；

The output of differential PWM modulation device inputs to logic controller, logic controller output square-wave signal d, square-wave signal d inputs the grid to PMOS MP by the first buffer and through not gate, square-wave signal d is by the grid of the second buffer input to NMOS tube MN, the drain electrode of the drain electrode of PMOS MP and NMOS tube MN is connected with one end of inductance L simultaneously, the other end of inductance L and resistance R_SOne end connect, resistance R_SThe other end and electrochemical capacitor C_OUTPositive pole connect, electrochemical capacitor C_OUTThe source electrode of negative pole and NMOS tube MN connect power supply ground simultaneously；The source electrode of PMOS MP meets the positive pole V of power supply_IN。

Wherein, differential PWM modulation device, logic controller and two buffers constitute PWM controller, are precisely controlled charging current, export fixed voltage.

Present embodiment needs to utilize resistance R_SOn differential voltage realize peak value or valley point current mould PWM, so adopting differential PWM modulation device as shown in Figure 5, including:

Differential amplifier, for input reference voltage V_REFAnd feedback voltage V_OUT, it is thus achieved that single-ended control voltage V_CTRL；

Gain stage A1, for by single-ended control voltage V_CTRLWith common-mode voltage V_COMDifferential voltage V_CTRL–V_COMAmplify, it is thus achieved that differential signal V_A1；

Gain stage A2, for amplifying the differential voltage of feedback current, it is thus achieved that differential signal V_A2；

Comparator CMP, for by differential signal V_A1With differential signal V_A2Produce PWM output more afterwards.

Gain stage A1, gain stage A2 and comparator CMP implement circuit as shown in Figure 6, and gain stage A1 includes NMOS tube M_A1, NMOS tube M_A2, resistance R₁, resistance R₂With current source I_A1；

NMOS tube M_A1Grid input control voltage V_CTRL, NMOS tube M_A2Grid common mode input V_COM；

NMOS tube M_A1Source electrode and NMOS tube M_A2Source electrode meet current source I simultaneously_A1；

NMOS tube M_A1Drain electrode and resistance R₁One end connect, resistance R₁The other end and resistance R₂One end connect, resistance R₂The other end and NMOS tube M_A2Drain electrode connect；

NMOS tube M_A2Drain electrode output and NMOS tube M_A1Drain electrode output input compare to comparator CMP.

In Fig. 6, gain stage A2 includes nmos pass transistor M_B1, nmos pass transistor M_B2With current source I_A2；

NMOS tube M_B1Grid input the first feedback voltage CS, NMOS tube M_B2Grid input the second feedback voltage V_OUT；First feedback voltage CS and the second feedback voltage V_OUTThe differential voltage that difference is feedback current；

NMOS tube M_B1Source electrode and NMOS tube M_B2Source electrode meet current source I simultaneously_A2；

NMOS tube M_B2Drain electrode output and NMOS tube M_B1Drain electrode output input compare to comparator CMP.

In Fig. 6, the differential voltage CS V of kinetic current mould DC-DC converter output electric current_OUTAmplify through gain stage A2, the differential voltage V of reaction controlling voltage_CTRL–V_COMAmplify through gain stage A1, obtain the differential signal V of reaction four road signals_P2–V_N2, through comparator CMP relatively after produce PWM output.

Common-mode voltage V in present embodiment_COMGeneration circuit as it is shown in fig. 7, specifically include: NMOS tube M_S1, NMOS tube M_S2, electric capacity C_COMWith current source Icom；

NMOS tube M_S1Source electrode and NMOS tube M_S2Drain electrode connect, NMOS tube M_S1Grid and drain electrode meet current source Icom and electric capacity C simultaneously_COMOne end, electric capacity C_COMThe other end and NMOS tube M_S2Source electrode connect；NMOS tube M_S2Grid connect square-wave signal d；

NMOS tube M_S1Drain electrode and described electric capacity C_COMOne end between voltage be common-mode voltage V_COM。

In present embodiment, it is provide bias current for it that current source connects the grid of NMOS tube；

Wherein, as shown in Figure 8, this square-wave signal is identical with the square-wave signal d in Fig. 3 for the oscillogram of square-wave signal d；

Common-mode voltage V_COMWaveform such as Fig. 9, on the one hand it is for controlling voltage V_CTRLThere is provided a reference voltage, on the other hand, by square-wave signal d and electric capacity C_COMCooperation realize slope compensation, it is ensured that the steady operation of peak value or valley point current mould DCDC.

In the present embodiment, use all can be separated or combine to variant embodiment.

Obviously, this utility model can be carried out various change and modification without deviating from spirit and scope of the present utility model by those skilled in the art.So, if these amendments of the present utility model and modification belong within the scope of this utility model claim and equivalent technologies thereof, then this utility model is also intended to comprise these change and modification.

Claims (7)

1. differential PWM modulation device, it is characterised in that described manipulator includes:

Differential amplifier, for input reference voltage V_REFAnd feedback voltage V_OUT, it is thus achieved that single-ended control voltage V_CTRL；

Gain stage A1, for by single-ended control voltage V_CTRLWith common-mode voltage V_COMDifferential voltage V_CTRL–V_COMAmplify, it is thus achieved that differential signal V_A1；

Gain stage A2, for amplifying the differential voltage of feedback current, it is thus achieved that differential signal V_A2；

Comparator, for by differential signal V_A1With differential signal V_A2Produce PWM output more afterwards.

2. differential PWM modulation device according to claim 1, it is characterised in that described common-mode voltage V_COM, it is additionally operable to slope compensation.

3. differential PWM modulation device according to claim 2, it is characterised in that described common-mode voltage V_COMGeneration circuit include NMOS tube M_S1, NMOS tube M_S2, electric capacity C_COMWith current source Icom；

NMOS tube M_S1Source electrode and NMOS tube M_S2Drain electrode connect, NMOS tube M_S1Grid and drain electrode meet current source Icom and electric capacity C simultaneously_COMOne end, electric capacity C_COMThe other end and NMOS tube M_S2Source electrode connect；NMOS tube M_S2Grid connect square-wave signal d；

NMOS tube M_S1Drain electrode and described electric capacity C_COMOne end between voltage be common-mode voltage V_COM。

4. the differential PWM modulation device according to claim 1 or 3, it is characterised in that described gain stage A1 includes NMOS tube M_A1, NMOS tube M_A2, resistance R₁, resistance R₂With current source I_A1；

NMOS tube M_A1Grid input control voltage V_CTRL, NMOS tube M_A2Grid common mode input V_COM；

NMOS tube M_A1Source electrode and NMOS tube M_A2Source electrode meet current source I simultaneously_A1；

NMOS tube M_A1Drain electrode and resistance R₁One end connect, resistance R₁The other end and resistance R₂One end connect, resistance R₂The other end and NMOS tube M_A2Drain electrode connect；

NMOS tube M_A2Drain electrode output and NMOS tube M_A1Drain electrode output input compare to comparator.

5. differential PWM modulation device according to claim 4, it is characterised in that described gain stage A2 includes nmos pass transistor M_B1, nmos pass transistor M_B2With current source I_A2；

NMOS tube M_B1Grid input the first feedback voltage CS, NMOS tube M_B2Grid input the second feedback voltage V_OUT；Described first feedback voltage CS and described second feedback voltage V_OUTThe differential voltage that difference is feedback current；

NMOS tube M_B1Source electrode and NMOS tube M_B2Source electrode meet current source I simultaneously_A2；

NMOS tube M_B2Drain electrode output and NMOS tube M_B1Drain electrode output input compare to comparator.

6. based on the DC/DC transducer of the differential PWM modulation device described in claim 1 or 5, it is characterised in that the detection resistance R of described DC/DC transducer_SIt is arranged in outgoing route, utilizes resistance R_SOn differential voltage realize peak value or valley point current mould PWM, described resistance R_SOn differential voltage be the differential voltage of described feedback current.

7. the DC/DC transducer based on differential PWM modulation device according to claim 6, it is characterized in that, described DC/DC transducer includes differential PWM modulation device, logic controller, two buffers, not gate, NMOS tube MN, PMOS MP, inductance L, electrochemical capacitor C_OUTWith resistance R_S；

The output of differential PWM modulation device inputs to logic controller, described logic controller output square-wave signal d, described square-wave signal d inputs the grid to PMOS MP by the first buffer and through not gate, described square-wave signal d is by the grid of the second buffer input to NMOS tube MN, the drain electrode of the drain electrode of described PMOS MP and NMOS tube MN is connected with one end of inductance L simultaneously, the other end of described inductance L and resistance R_SOne end connect, described resistance R_SThe other end and electrochemical capacitor C_OUTPositive pole connect, described electrochemical capacitor C_OUTThe source electrode of negative pole and NMOS tube MN connect power supply ground simultaneously；The source electrode of described PMOS MP meets the positive pole V of power supply_IN。