1. A switching amplifier comprising:
an input stage that receives analog signals as its input and having it modulated into a digital output whose average value is directly proportional to the input signal’s instantaneous amplitude; and
output DC offset protection, for generating a shutdown signal responsive to a DC component at the switching amplifier output.
2. The switching amplifier of claim 1, wherein the DC offset protection comprises:
a first low pass filter and second low pass filter, for filtering pulse width modulated signals;
a comparator, for comparing the signals;
a pulse edge detector, for minimizing jitter and producing a pulse;
a clock generator, for producing continuous pulse
a counter and offset protection logic, for issuing a shutdown signal if an output DC offset is present.
3. The switching amplifier of claim 2, wherein the DC offset protection is coupled to the output of the said switching amplifier.
4. The switching amplifier of claim 3, wherein the output of the amplifier are used as input signals to the first and second low pass filter.
5. The switching amplifier of claim 3, wherein the said first and second low pass filter is a first order RC low pass filter.
6. The switching amplifier of claim 3, wherein the filtered output of the first and second low pass filter are inputted and compared by the comparator and provides a pulsating high or a low output depending on which input is higher.
7. The switching amplifier of claim 3, wherein the comparator output is used as an input for the pulse edge detector.
8. The switching amplifier of claim 3, wherein the pulse edge detector produces a pulse signals to be applied as a reset for the counter.
9. The switching amplifier of claim 3, wherein the clock generator provides continues pulse to the counter.
10. The switching amplifier of claim 3, wherein the counter produces a signal after counting a predetermined time, if no reset signal is received from the pulse edge detector within said predetermined time.
11. The switching amplifier of claim 1, wherein the DC offset protection uses a filterless architecture.
12. A method of protecting a switching amplifier against output DC offset comprising:
comparing a first filtered output signal with a predetermined threshold voltage and generating a reset signal;
generating an offset protection signal to deactivate the said switching amplifier if the said reset signal is not activated during a predetermined time period.
13. The method according to claim 12, wherein the said first filtered output signal is derived from a first output signal of the said switching amplifier.
14. The method according to claim 12, wherein the said predetermined threshold voltage is a dc reference voltage.
15. The method according to claim 12, wherein the said predetermined threshold voltage is a second filtered output signal derived from a second output signal of the said switching amplifier.
16. The method according to claim 12, wherein the said reset signal is a function of the said first filtered output signal and the said predetermined threshold voltage.
17. The method according to claim 12, wherein the function of the said offset protection signal is to transfer the state of the said switching amplifier to another state that will not cause constant dc current flow to a load of the said switching amplifier.
18. The method according to claim 13, wherein the said first output signal can be a PWM, PDM or sigma Delta modulated switching signal.
19. The method according to claim 15, wherein the said second output signal can be a PWM, PDM or sigma Delta modulated switching signal.
20. The method according to claim 17, wherein the said load of the said switching amplifier can be a resistive load, a capacitive load or an inductive load.
21. A switching amplifier comprising:
a first driver arrangement for producing a first amplified output signal having a positive phase;
a second driver arrangement for producing a second amplified output signal having a negative phase which is opposite to said positive phase; and
a DC offset protection arrangement for comparing said first and second amplified output signals, and for producing a shutdown signal when there is no signal overlap between said first and second amplified output signals after a predetermined time.
22. A method of protecting a switching amplifier from output DC offset, comprising:
producing a first amplified output signal having a positive phase;
producing a second amplified output signal having a negative phase which is opposite to said positive phase;
comparing said first and second amplified output signals, and
producing a shutdown signal when there is no signal overlap between said first and second amplified output signals after a predetermined time.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A system of recycling exhaust heat from an internal combustion engine, the system comprising:
a working fluid circulating line configured to rotate a turbine with a working fluid vaporized by heat received from an EGR line of the internal combustion engine;
an EGR side heat exchanging unit configured to perform a heat exchange between an EGR gas and the working fluid to thereby cool the EGR gas and transfer heat from the EGR gas to the working fluid; and
a gas-liquid separator configured to be formed between the EGR side heat exchanging unit and the turbine to thereby supply only a gas component of the working fluid to the turbine.
2. The system according to claim 1, wherein the gas-liquid separator includes:
a liquid receiving chamber capable of receiving the working fluid in a liquid state therein; and
a communicating pipe fluidically-communicating a turbine introducing pipe, which is a conduit connecting the turbine to the EGR side heat exchanging unit, and the liquid receiving chamber with each other.
3. The system according to claim 2, wherein the communicating pipe includes a first communicating pipe disposed to be adjacent to the EGR side heat exchanging unit and a second communicating pipe disposed to be adjacent to the turbine.
4. The system according to claim 3, wherein a diameter of a portion connected to the first communicating pipe of the turbine introducing pipe is substantially the same as a diameter of a portion connected to the second communicating pipe of the turbine introducing pipe.
5. The system according to claim 2, wherein the liquid receiving chamber is disposed at a lower position than the turbine introducing pipe.
6. The system according to claim 2, wherein the communicating pipe has an upper end portion connected to a side portion or a lower portion of the turbine introducing pipe.
7. The system according to claim 1, further comprising an exhaust side heat exchanging unit installed at an exhaust line discharging an exhaust gas to an outside to thereby transfer heat from the exhaust gas to the working fluid.
8. The system according to claim 7, wherein the exhaust side heat exchanging unit is disposed at a higher side of the working fluid circulating line than the EGR side heat exchanging unit.
9. The system according to claim 7, wherein the working fluid always passes through the exhaust side heat exchanging unit, and
the working fluid passes through the EGR side heat exchanging unit only when a temperature of the exhaust gas flowing in the EGR line is equal to or greater than a specific temperature T1.
10. The system according to claim 9, wherein the specific temperature T1 is 500\xb0 C.