Transceiver suitable for IO-Link devices and related IO-Link device
A transceiver is connectable to a cable with at least three wires. The transceiver may include a controlled output stage including a high-side leg, having two P-type transistors coupled in series and having a common current terminal, coupled between an output pin and a positive supply pin. The P-type transistors have body regions coupled to the common current terminal of the high-side leg. A low-side leg, includes two N-type transistors coupled in series and having a common current terminal, coupled between the output pin and a negative supply pin. The N-type transistors have body regions coupled to the common current terminal of the low-side leg. The protection circuit also includes a voltage clamper coupled between the common current terminals.
1. A transceiver suitable for IO-Link™ devices, connectable to a cable with at least three wires, comprising:
a positive supply pin connectable to a positive supply wire of the cable on which a positive supply voltage is made available;
a negative supply pin connectable to a negative supply wire of the cable on which a negative supply voltage is made available;
at least one input/output pin connectable to a digital data wire of the cable configured to receive/transmit data signals switching between the positive supply voltage and negative supply voltage from/to IO-Link™ devices connected to the cable;
inner functional blocks;
an internal positive voltage line;
an internal negative voltage line; and
a controlled output stage configured to connect said at least one input/output pin to said positive supply pin or to said negative supply pin, including a protection circuit for said inner functional blocks against reverse polarity due to a wrong connection of said positive and negative supply pins to respective wires of the cable;
said controlled output stage comprising
a high-side leg, comprising two P-type transistors connected in series between them such as to have a common current terminal, coupled between said at least one input/output pin and said positive supply pin, the common current terminal being connected to said internal positive voltage line, said P-type transistors having body regions being shorted to the common current terminal, and
a low-side leg, comprising two N-type transistors connected in series between them such as to have a common current terminal, coupled between said at least one input/output pin and said negative supply pin, the common current terminal being connected to said internal negative voltage line, said N-type transistors having body regions being shorted to the common current terminal; and
a driver comprising a first current path extending between a positive supply terminal and the common current terminal of the high-side leg, and a second current path extending between a negative supply terminal and common current terminal of the low-side leg, and being configured to turn on/off said two P-type and two N-type transistors to allow transmission on the digital data wire;
said protection circuit comprising a voltage clamper connected between the common current terminal for said high-side leg and the common current terminal for said low-side leg, configured to enter in a conduction state in case of overvoltage on the internal negative and positive supply voltage lines.
2. The transceiver of claim 1 , wherein said voltage clamper comprises a power transistor connected to short said common current terminals when in a conduction state; and a bias Zener diode connected between a control terminal of said power transistor and the common current terminal of said high-side leg, configured to enter in a conduction state and to cause a voltage drop suitable for turning on said power transistor in case of an overvoltage on said internal negative and positive supply voltage lines.
3. The transceiver of claim 2 , further comprising a bias resistor connected between said control terminal of the power transistor and the common current terminal of said low-side leg.
4. The transceiver of claim 1 , wherein said at least one input/output pin comprises a high-side input/output pin and a low-side input/output pin, both connectable to the data wire of the cable, said high-side leg being connected between said high-side input/output pin and said positive supply pin, and said low-side leg being connected between said low-side input/output pin and said negative supply pin.
5. The transceiver of claim 1 , wherein said protection circuit is realized in integrated form along with said inner functional blocks.
6. An electronic device connectable to a cable with at least three wires, comprising:
a positive supply pin connectable to a positive supply wire of the cable;
a negative supply pin connectable to a negative supply wire of the cable;
at least one output pin connectable to a digital data wire of the cable; and
a controlled output stage comprising
a high-side leg, comprising two P-type transistors coupled in series and having a common current terminal, coupled between said at least one output pin and said positive supply pin, said P-type transistors having body regions coupled to the common current terminal,
a low-side leg, comprising two N-type transistors coupled in series and having a common current terminal, coupled between said at least one output pin and said negative supply pin, said N-type transistors having body regions coupled to the common current terminal,
a driver comprising a first current path extending between a positive supply terminal and the common current terminal of the high-side leg, and a second current path extending between a negative supply terminal and common current terminal of the low-side leg, and being configured to turn on/off said two P-type and two N-type transistors, and
a protection circuit comprising a voltage clamper coupled between the common current terminal for said high-side leg and the common current terminal for said low-side leg.
7. The electronic device of claim 6 , further comprising inner functional blocks; and wherein said protection circuit is configured for protecting said inner functional blocks against reverse polarity due to a wrong connection of said positive and negative supply pins to respective wires of the cable.
8. The electronic device of claim 6 , wherein said voltage clamper comprises a power transistor coupled to short the common current terminals when in a conduction state; and a Zener diode coupled between a control terminal of said power transistor and the common current terminal of said high-side leg.
9. The electronic device of claim 8 , further comprising a bias resistor coupled between the control terminal of said power transistor and the common current terminal of said low-side leg.
10. The electronic device of claim 6 , wherein said at least one output pin comprises a high-side output pin and a low-side output pin, both connectable to the data wire of the cable, said high-side leg being coupled between said high-side output pin and said positive supply pin, and said low-side leg being coupled between said low-side output pin and said negative supply pin.
11. The electronic device of claim 6 , wherein said protection circuit is realized in integrated form.
12. The electronic device of claim 6 , wherein said positive supply pin, negative supply pin, at least one output pin, and controlled output stage define an IO-Link™ device transceiver.
13. The electronic device of claim 12 , further comprising a microcontroller coupled to said IO-Link™ device transceiver.
14. An method for making an electronic device connectable to a cable with at least three wires, the electronic device comprising a positive supply pin connectable to a positive supply wire of the cable, a negative supply pin connectable to a negative supply wire of the cable, and at least one output pin connectable to a digital data wire of the cable; the method comprising:
forming a controlled output stage comprising
a high-side leg, comprising two P-type transistors coupled in series and having a common current terminal, coupled between the at least one output pin and the positive supply pin, the P-type transistors having body regions coupled to the common current terminal,
a low-side leg, comprising two N-type transistors coupled in series and having a common current terminal, coupled between the at least one output pin and the negative supply pin, the N-type transistors having body regions coupled to the common current terminal,
a driver comprising a first current path extending between a positive supply terminal and the common current terminal of the high-side leg, and a second current path extending between a negative supply terminal and common current terminal of the low-side leg, and being configured to turn on/off the two P-type and two N-type transistors to allow transmission on the digital data wire, and
a protection circuit comprising a voltage clamper coupled between the common current terminal for the high-side leg and the common current terminal for the low-side leg.
15. The method of claim 14 , wherein the protection circuit is configured for protecting inner functional blocks of the electronic device against reverse polarity due to a wrong connection of the positive and negative supply pins to respective wires of the cable.
16. The method of claim 14 , wherein the voltage clamper comprises a power transistor coupled to short the common current terminals when in a conduction state; and a Zener diode coupled between a control terminal of the power transistor and the common current terminal of the high-side leg.
17. The method of claim 16 , further comprising a bias resistor coupled between the control terminal of the power transistor and the common current terminal of the low-side leg.
18. The method of claim 14 , wherein the protection circuit is realized in integrated form.
19. The method of claim 14 , wherein the positive supply pin, negative supply pin, at least one output pin, and controlled output stage define an IO-Link™ device transceiver.